GMSH curved meshes support

Thanks to Daniel and everyone involved for bringing the wonderful GMSH mesh support to Trixi in https://github.com/trixi-framework/Trixi.jl/pull/1799!!

I am unable to get the current parser to handle a GMSH generated mesh with curved boundaries. Here is how I generate a curved mesh with GMSH (I only know how to do it with GUI at this moment). I tried this with `NACA6412.geo` available [here](https://trixi-framework.github.io/Trixi.jl/stable/tutorials/p4est_from_gmsh/) and another one [here](https://github.com/cpraveen/taxis/blob/master/examples/cylinder_turek/cylinder.geo)

1) Open the .geo file in GMSH
2) Click Modules -> Mesh -> 2D (Generates the straight sided mesh)
3) Click Modules -> Mesh -> Set order 2 (curves the mesh boundary to be order 2. Higher is also possible)
4) File -> Export -> mesh_NACA6412.inp, making sure to tick "Save all elements" and "Save groups of nodes" (Exporting with these options ticked is the step I cannot do via command line)

If I skip step 3, the parser can handle it fine and I am able to run the available elixir https://github.com/trixi-framework/Trixi.jl/blob/main/examples/p4est_2d_dgsem/elixir_euler_NACA6412airfoil_mach2.jl. However, if I try to run same the elixir when I did the above step 3 to curve the mesh, I get a segmentation fault in the line that reads the mesh, i.e., `mesh = P4estMesh{2}(mesh_file, polydeg = polydeg, boundary_symbols = boundary_symbols)`

It starts with
```shell
[p4est] No elements or nodes found in mesh file.
[p4est] Failed to read /home2/arpit/repositories/cloned/Trixi.jl/examples/p4est_2d_dgsem/NACA6412_curved.inp: pass 1
```

Full error message


P4est segmentation fault

```shell
[p4est] No elements or nodes found in mesh file.
[p4est] Failed to read /home2/arpit/repositories/cloned/Trixi.jl/examples/p4est_2d_dgsem/NACA6412_curved.inp: pass 1

[595759] signal (11.1): Segmentation fault
in expression starting at /home2/arpit/repositories/cloned/Trixi.jl/examples/p4est_2d_dgsem/elixir_euler_NACA6412airfoil_mach2.jl:78
unsafe_load at ./pointer.jl:119 [inlined]
unsafe_load at /home2/arpit/.julia/packages/P4est/0rTeV/src/pointerwrappers.jl:86 [inlined]
getindex at /home2/arpit/.julia/packages/P4est/0rTeV/src/pointerwrappers.jl:82 [inlined]
getindex at /home2/arpit/.julia/packages/P4est/0rTeV/src/pointerwrappers.jl:82 [inlined]
p4est_mesh_from_standard_abaqus at /home2/arpit/repositories/cloned/Trixi.jl/src/meshes/p4est_mesh.jl:460
#_#279 at /home2/arpit/repositories/cloned/Trixi.jl/src/meshes/p4est_mesh.jl:376
P4estMesh at /home2/arpit/repositories/cloned/Trixi.jl/src/meshes/p4est_mesh.jl:353
unknown function (ip: 0x7f420e7c66a0)
_jl_invoke at /cache/build/builder-amdci4-6/julialang/julia-release-1-dot-10/src/gf.c:2894 [inlined]
ijl_apply_generic at /cache/build/builder-amdci4-6/julialang/julia-release-1-dot-10/src/gf.c:3076
jl_apply at /cache/build/builder-amdci4-6/julialang/julia-release-1-dot-10/src/julia.h:1982 [inlined]
do_call at /cache/build/builder-amdci4-6/julialang/julia-release-1-dot-10/src/interpreter.c:126
eval_value at /cache/build/builder-amdci4-6/julialang/julia-release-1-dot-10/src/interpreter.c:223
eval_stmt_value at /cache/build/builder-amdci4-6/julialang/julia-release-1-dot-10/src/interpreter.c:174 [inlined]
eval_body at /cache/build/builder-amdci4-6/julialang/julia-release-1-dot-10/src/interpreter.c:617
jl_interpret_toplevel_thunk at /cache/build/builder-amdci4-6/julialang/julia-release-1-dot-10/src/interpreter.c:775
jl_toplevel_eval_flex at /cache/build/builder-amdci4-6/julialang/julia-release-1-dot-10/src/toplevel.c:934
jl_toplevel_eval_flex at /cache/build/builder-amdci4-6/julialang/julia-release-1-dot-10/src/toplevel.c:877
ijl_toplevel_eval_in at /cache/build/builder-amdci4-6/julialang/julia-release-1-dot-10/src/toplevel.c:985
eval at ./boot.jl:385 [inlined]
include_string at ./loading.jl:2070
_jl_invoke at /cache/build/builder-amdci4-6/julialang/julia-release-1-dot-10/src/gf.c:2894 [inlined]
ijl_apply_generic at /cache/build/builder-amdci4-6/julialang/julia-release-1-dot-10/src/gf.c:3076
_include at ./loading.jl:2130
include at ./client.jl:489
unknown function (ip: 0x7f420e7b5b55)
_jl_invoke at /cache/build/builder-amdci4-6/julialang/julia-release-1-dot-10/src/gf.c:2894 [inlined]
ijl_apply_generic at /cache/build/builder-amdci4-6/julialang/julia-release-1-dot-10/src/gf.c:3076
jl_apply at /cache/build/builder-amdci4-6/julialang/julia-release-1-dot-10/src/julia.h:1982 [inlined]
do_call at /cache/build/builder-amdci4-6/julialang/julia-release-1-dot-10/src/interpreter.c:126
eval_value at /cache/build/builder-amdci4-6/julialang/julia-release-1-dot-10/src/interpreter.c:223
eval_stmt_value at /cache/build/builder-amdci4-6/julialang/julia-release-1-dot-10/src/interpreter.c:174 [inlined]
eval_body at /cache/build/builder-amdci4-6/julialang/julia-release-1-dot-10/src/interpreter.c:617
jl_interpret_toplevel_thunk at /cache/build/builder-amdci4-6/julialang/julia-release-1-dot-10/src/interpreter.c:775
jl_toplevel_eval_flex at /cache/build/builder-amdci4-6/julialang/julia-release-1-dot-10/src/toplevel.c:934
jl_toplevel_eval_flex at /cache/build/builder-amdci4-6/julialang/julia-release-1-dot-10/src/toplevel.c:877
jl_toplevel_eval_flex at /cache/build/builder-amdci4-6/julialang/julia-release-1-dot-10/src/toplevel.c:877
jl_toplevel_eval_flex at /cache/build/builder-amdci4-6/julialang/julia-release-1-dot-10/src/toplevel.c:877
ijl_toplevel_eval_in at /cache/build/builder-amdci4-6/julialang/julia-release-1-dot-10/src/toplevel.c:985
eval at ./boot.jl:385 [inlined]
eval_user_input at /cache/build/builder-amdci4-6/julialang/julia-release-1-dot-10/usr/share/julia/stdlib/v1.10/REPL/src/REPL.jl:150
repl_backend_loop at /cache/build/builder-amdci4-6/julialang/julia-release-1-dot-10/usr/share/julia/stdlib/v1.10/REPL/src/REPL.jl:246
#start_repl_backend#46 at /cache/build/builder-amdci4-6/julialang/julia-release-1-dot-10/usr/share/julia/stdlib/v1.10/REPL/src/REPL.jl:231
start_repl_backend at /cache/build/builder-amdci4-6/julialang/julia-release-1-dot-10/usr/share/julia/stdlib/v1.10/REPL/src/REPL.jl:228
_jl_invoke at /cache/build/builder-amdci4-6/julialang/julia-release-1-dot-10/src/gf.c:2894 [inlined]
ijl_apply_generic at /cache/build/builder-amdci4-6/julialang/julia-release-1-dot-10/src/gf.c:3076
#run_repl#59 at /cache/build/builder-amdci4-6/julialang/julia-release-1-dot-10/usr/share/julia/stdlib/v1.10/REPL/src/REPL.jl:389
run_repl at /cache/build/builder-amdci4-6/julialang/julia-release-1-dot-10/usr/share/julia/stdlib/v1.10/REPL/src/REPL.jl:375
jfptr_run_repl_91689.1 at /home2/arpit/.local/julia-1.10.0/lib/julia/sys.so (unknown line)
_jl_invoke at /cache/build/builder-amdci4-6/julialang/julia-release-1-dot-10/src/gf.c:2894 [inlined]
ijl_apply_generic at /cache/build/builder-amdci4-6/julialang/julia-release-1-dot-10/src/gf.c:3076
#1013 at ./client.jl:432
jfptr_YY.1013_82677.1 at /home2/arpit/.local/julia-1.10.0/lib/julia/sys.so (unknown line)
_jl_invoke at /cache/build/builder-amdci4-6/julialang/julia-release-1-dot-10/src/gf.c:2894 [inlined]
ijl_apply_generic at /cache/build/builder-amdci4-6/julialang/julia-release-1-dot-10/src/gf.c:3076
jl_apply at /cache/build/builder-amdci4-6/julialang/julia-release-1-dot-10/src/julia.h:1982 [inlined]
jl_f__call_latest at /cache/build/builder-amdci4-6/julialang/julia-release-1-dot-10/src/builtins.c:812
#invokelatest#2 at ./essentials.jl:887 [inlined]
invokelatest at ./essentials.jl:884 [inlined]
run_main_repl at ./client.jl:416
exec_options at ./client.jl:333
_start at ./client.jl:552
jfptr__start_82703.1 at /home2/arpit/.local/julia-1.10.0/lib/julia/sys.so (unknown line)
_jl_invoke at /cache/build/builder-amdci4-6/julialang/julia-release-1-dot-10/src/gf.c:2894 [inlined]
ijl_apply_generic at /cache/build/builder-amdci4-6/julialang/julia-release-1-dot-10/src/gf.c:3076
jl_apply at /cache/build/builder-amdci4-6/julialang/julia-release-1-dot-10/src/julia.h:1982 [inlined]
true_main at /cache/build/builder-amdci4-6/julialang/julia-release-1-dot-10/src/jlapi.c:582
jl_repl_entrypoint at /cache/build/builder-amdci4-6/julialang/julia-release-1-dot-10/src/jlapi.c:731
main at julia (unknown line)
__libc_start_main at /lib/x86_64-linux-gnu/libc.so.6 (unknown line)
unknown function (ip: 0x4010b8)
Allocations: 25176877 (Pool: 25169453; Big: 7424); GC: 90
Segmentation fault
```

Note that the `.geo` file does have enough information to curve the mesh, see images in spoilers below. Here is `gmsh` showing a straight sided mesh

Straight sided GMSH mesh


The curved airfoil already indicates that it is possible to curve the mesh. And, by setting a high order with `Set order 3`, I get

GMSH mesh of order 3


`HOHQ` generated meshes also give curved boundaries already.

Here is a gist with `.inp` file generated with curved boundaries - https://[gist.githubusercontent.com/Arpit-Babbar/d9238c194b3e87574fdcbbd39fa59180/raw/6c985a65b58e5eda38630b6a8d3e54652293650a/NACA6412_curved.inp](https://gist.githubusercontent.com/Arpit-Babbar/d9238c194b3e87574fdcbbd39fa59180/raw/6c985a65b58e5eda38630b6a8d3e54652293650a/NACA6412_curved.inp)

Here is a gist with `.inp` file generated with straight sided boundaries - https://[gist.githubusercontent.com/Arpit-Babbar/f4271dc9c57724bf62681c725aa16cd6/raw/e83e50d4f67ee1853f189d6b7269e8fb1cde5ab0/NACA6412.inp](https://gist.githubusercontent.com/Arpit-Babbar/f4271dc9c57724bf62681c725aa16cd6/raw/e83e50d4f67ee1853f189d6b7269e8fb1cde5ab0/NACA6412.inp)

Start with src/meshes/p4est_mesh.jl, especially p4est_mesh_from_standard_abaqus around line 460 and the P4estMesh constructor used by examples/p4est_2d_dgsem/elixir_euler_NACA6412airfoil_mach2.jl. Run that elixir with the curved NACA6412.inp gist and compare it with the straight-sided input. Done means curved GMSH meshes load without the reported missing-elements error or segmentation fault.

Written by the indexing model from the issue text.