LACP: rollback vlan setting, fix perf endpoints generation

[enhaut]

Description

This MR includes:

• fix for rollbacking VLAN settings on Dell switches - Assigning port to a channel group has side effect of disconnecting it from all the VLANS. Those are not automatically restored after removing port from channel group.

• perf endpoint generation fix - UDP over LACP requires lots of parallel perf processes. However, due to generating IP perf endpoints by doing a product on source and dest IPs recipe generated A WAY more processes (all IPs+ports to all IPS+ports) than expected.

(see commit messages for further explanation)

Tests

Rollback tests:

• manually verified on switch side
• LACP recipes interleaved with VLAN testsJ:8926338

Endpoints generation fix:

• J:8932918 just a functional test of UDP test, without changes the recipe got aborted due to machine freeze

Reviews

@jtluka

[enhaut]

Approach discussed with dell support, there is no other way of assigning multiple ports to VLANs nor getting VLAN ports with just a single HTTP request.

So this can be merged.