staticd: Extend `static_zebra_request_srv6_sid` to request SRv6 uA SIDs
In order to configure an SRv6 uA SID in staticd, staticd should request
SRv6 SID Manager to allocate a SID bound to the uA behavior.
Currently, `static_zebra_request_srv6_sid` does not support requesting
SIDs bound to the uA behavior.
This commit extends the `static_zebra_request_srv6_sid` function to
enable staticd to request SIDs bound to the uA behavior.