[Arc] Support hw.wires of aggregate types

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When i run `arcilator` with `$ ./arcilator a.mlir --state-file=a.json` i get the following error:
```
a.mlir:9:23: error: 'arc.tap' op operand #0 must be signless integer, but got '!hw.struct'
%_registers_0_T = hw.wire %2 sym @sym_0 : !hw.struct
^
a.mlir:9:23: note: see current operation: "arc.tap"(%5) {name = "_registers_0_T"} : (!hw.struct) -> ()
```

`a.mlir`:
```
module {
hw.module @Barrier(in %clock : !seq.clock, in %reset : i1, in %io_input : !hw.array<1xstruct>, out io_output : !hw.array<1xstruct>) {
%false = hw.constant false
%0 = hw.array_get %io_input[%false] : !hw.array<1xstruct>, i1
%valid = hw.struct_extract %0["valid"] : !hw.struct
%registers = seq.firreg %3 clock %clock sym @sym {firrtl.random_init_start = 0 : ui64} : !hw.array<1xstruct>
%1 = hw.array_get %registers[%false] : !hw.array<1xstruct>, i1
%2 = comb.mux bin %valid, %0, %1 : !hw.struct
%_registers_0_T = hw.wire %2 sym @sym_0 : !hw.struct
%3 = hw.array_create %_registers_0_T : !hw.struct
hw.output %registers : !hw.array<1xstruct>
}
}
```

Reproduce the failure with arcilator using the provided a.mlir input and inspect the hw.wire and arc.tap operations involved in the diagnostic. Trace how aggregate operands are handled, then verify that the same input no longer rejects the !hw.struct value and add or run a regression test if the relevant test location can be identified.

Written by the indexing model from the issue text.