[DO NOT MERGE] passpoint: validate decorated identity prefix

Bug: 246539931
Test: atest FrameworksWifiTests
      insatll PoC to verify the issue does not happen
Change-Id: I59144c43d2ee9590c8d973e24877e56aaf395b33
(cherry picked from commit df9d477011d9e64857dea3658cba1fc25e5d18cc)
(cherry picked from commit 68abe8f2737d6fd3c0a0ccf9e4664dd747aa9a74)
Merged-In: I59144c43d2ee9590c8d973e24877e56aaf395b33
1 file changed