bluetooth: host: adv: Release buf if failed to set addr

The `bt_id_set_adv_own_addr` function itself tries to allocate a buffer
for the command and it failes due to lack of buffers, it returns error.
However, the `le_ext_adv_param_set` function doesn't handle the error
properly and keeps its own allocated buffer.

This commit releases the allocated buffer.
Partially fixes mesh in #77241.

Signed-off-by: Pavel Vasilyev <pavel.vasilyev@nordicsemi.no>
(cherry picked from commit 2f024744)