[mlir][linalg] Fix builder API usage in `RegionBuilderHelper` (#87451)

Operations must be created with the supplied builder. Otherwise, the
dialect conversion / greedy pattern rewrite driver can break.

This commit fixes a crash in the dialect conversion:
```
within split at llvm-project/mlir/test/Conversion/TosaToLinalg/tosa-to-linalg-invalid.mlir:1 offset :8:8: error: failed to legalize operation 'tosa.add'
  %0 = tosa.add %1, %arg2 : (tensor<10x10xf32>, tensor<*xf32>) -> tensor<*xf32>
       ^
within split at llvm-project/mlir/test/Conversion/TosaToLinalg/tosa-to-linalg-invalid.mlir:1 offset :8:8: note: see current operation: %9 = "tosa.add"(%8, %arg2) : (tensor<10x10xf32>, tensor<*xf32>) -> tensor<*xf32>
mlir-opt: llvm-project/mlir/include/mlir/IR/UseDefLists.h:198: mlir::IRObjectWithUseList<mlir::OpOperand>::~IRObjectWithUseList() [OperandType = mlir::OpOperand]: Assertion `use_empty() && "Cannot destroy a value that still has uses!"' failed.
```

This commit is the proper fix for #87297 (which was reverted).