[mlir][sve] Add an e2e for linalg.matmul with mixed types (#73773)

Apart from the test itself, this patch also updates a few patterns to
fix how new VectorType(s) are created. Namely, it makes sure that
"scalability" is correctly propagated.

Regression tests will be updated seperately while auditing Vector
dialect tests in the context of scalable vectors:
  * https://github.com/orgs/llvm/projects/23