[mlir][Interfaces] `LoopLikeOpInterface`: Expose mutable inits/yielded values (#69137)

Expose a `MutableArrayRef<OpOperand>` instead of
`ValueRange`/`OperandRange`. This allows users of this interface to
change the yielded values and the init values. The names of the
interface methods are the same as the auto-generated op accessor names
(`get...()` returns `OperandRange`, `get...Mutable()` returns
`MutableOperandRange`).

Note: The interface methods return a `MutableArrayRef` instead of a
`MutableOperandRange` because a loop op may not implement
`getYieldedValuesMutable` etc. and there is no safe way to return an
"empty" range with a `MutableOperandRange`.