PTS: Avoid BR SDP after LE pairing

Use Case: Certification test case requiring LE secure pairing
with PTS.

Test Case: TP/SCJW/BV-01-C

Failure:
While pairing with PTS for certification test cases, LE secure
pairing followed by BR/EDR cross key derivation results in the
host initiating the SDP to gather the remote BR/EDR services.
PTS considers it as a test failure.

Fix: Added run time flag in bt_stack.conf file
"PTS_DisableSDPOnLEPair" to disable the SDP immidiately after
LE pairing followed by cross key derivation.

Bug: 27852645
Change-Id: Ib5a05c47b99c2ef8256967a608ae9ebbdfba60ee