Fix duplicate check for ACL rules with cidr

While checking for duplicate ACL rules, we were ignoring the prefix part. As a result, if two rules containing different prefixes were being added, we were treating them duplicates and were not adding the second rule. Added comparison of prefixes while comparing rules.

Also updated the unit test case for the same.

Closes-Bug: 1392545
(cherry picked from commit 2f31043a6819058eb1a641ce7f391ca7ba2822de)

Change-Id: I1dc1669826e3f9154f2876074c0eada58b59ac29