GBP-UI: L2P-create should not have drop down list of L3Ps

[puppet-py]

L2Policy is always created in the context of a L3Policy.
The create-window of L2Policy has drop down list of L3Ps, we should avoid that.

Reason: As auser he is creating L2P in the context of a given L3P. Its obvious that the L2P will be created in that L3P's context, but if he DOES NOT select the L3P from that drop-down list, it picks up the first L3P(which could be some other L3P) in the list and creates the L2P.

[Sumit Naiksatam (snaiksat)]

Agreed, we should just remove this drop down, and instead display a label with the chosen l3_policy's name:UUID.