[C++][CI] S3 tests fail with "Attempt to initialize S3 after it has been finalized"

### Describe the bug, including details regarding any error messages, version, and platform.

Some Linux Conda CI jobs fail on `arrow-filesystem-test` and `arrow-s3fs-module-test` since GCC 15.3.0 got picked up from `conda-forge`
- `test-conda-cpp-valgrind` nightly job https://github.com/ursacomputing/crossbow/actions/runs/32317149927/job/96271748148#step:6:3299
- `test-conda-cpp` (on PR) https://github.com/ursacomputing/crossbow/actions/runs/32375335577/job/96445246692#step:6:5496
- `AMD64 Conda C++ AVX2` (on PR) https://github.com/apache/arrow/actions/runs/32242684590/job/96036487405?pr=50903#step:8:5503

```console
[ RUN ] S3Test.FromUriRejectsUnknownOptions
/arrow/cpp/src/arrow/filesystem/s3fs_module_test.cc:138: Failure
Value of: _st.ToStringWithoutContextLines()
Expected: has substring "Unexpected option"
Actual: "Invalid: Attempt to initialize S3 after it has been finalized"

[ FAILED ] S3Test.FromUriRejectsUnknownOptions (0 ms)
[----------] 1 test from S3Test (0 ms total)

[----------] Global test environment tear-down
[==========] 4 tests from 2 test suites ran. (106 ms total)
[ PASSED ] 0 tests.
[ FAILED ] 4 tests, listed below:
[ FAILED ] S3ModuleTest.FromUri
[ FAILED ] S3ModuleTest.FromUriAndOptionsCredentials
[ FAILED ] S3ModuleTest.FromUriAndOptionsRetryStrategy
[ FAILED ] S3Test.FromUriRejectsUnknownOptions
```

EDIT:
conda-forge compilers 2.0 intentionally dropped flags (conda-forge/conda-forge.github.io#2595)

Previously with conda-forge compilers 1.11.0:
https://github.com/ursacomputing/crossbow/actions/runs/32084342044/job/95553621117#step:6:854
`-- CMAKE_CXX_FLAGS: -Wno-noexcept-type -Wno-self-move -fvisibility-inlines-hidden -fmessage-length=0 -march=nocona -mtune=haswell -ftree-vectorize -fPIC -fstack-protector-strong -fno-plt -O2 -ffunction-sections -pipe -isystem /opt/conda/envs/arrow/include -fdiagnostics-color=always -Wall -fno-semantic-interposition -msse4.2`

Now with conda-forge compilers 2.0.0:
https://github.com/ursacomputing/crossbow/actions/runs/32317149927/job/96271748148#step:6:848
`-- CMAKE_CXX_FLAGS: -Wno-noexcept-type -Wno-self-move -fdiagnostics-color=always -Wall -fno-semantic-interposition -msse4.2 `

### Component(s)

C++, Continuous Integration