[mlir][bufferization] Never pass ownership to functions (#80655)

Even when `private-function-dynamic-ownership` is set, ownership should
never be passed to the callee. This can lead to double deallocs (#77096)
or use-after-free in the caller because ownership is currently passed
regardless of whether there are any further uses of the buffer in the
caller or not.

Note: This is consistent with the fact that ownership is never passed to
nested regions.

This commit fixes #77096.