res_pjsip_session: Prevent user=phone being added to anonimized URIs.

Move ast_sip_add_usereqphone to be called after anonymization of URIs,
to prevent the user_eq_phone adding "user=phone" to URIs containing a
username that is not a phonenumber (RFC3261 19.1.1). An extra call to
ast_sip_add_usereqphone on the saved version before anonymization is
added to add user=phone" to the PAI.

ASTERISK-27047 #close

Change-Id: Ie5644bc66341b86dc08b1f7442210de2e6acdec6