TAPA queries NSM to re-use connection if possible

[zolug]

Description

TAPA uses a deterministic NSM Connection/Segment ID that does not change if connecting to [Conduit, Trench] tuple with the same names from the same application POD.

var nsName string = conduit.GetNetworkServiceNameWithProxy(c.Conduit.GetName(), c.Conduit.GetTrench().GetName(), c.Namespace)
var id string = fmt.Sprintf("%s-%s-%d", c.TargetName, nsName, 0)

In case NSM connection Close() fails for example on the TAPA side for some reason (or the TAPA container crashes), then requesting a new connection with the same Connection ID will create a second connection in NSM.
Unfortunately, once the "old" connection's token lifetime expires, and NSM orders clean-up, it will trigger a heal event in TAPA because of the shared Connection ID.
This will lead to unwanted NSM connection reconnect. Also, in general having multiple NSM connections that share the same TAPA connection/segment ID is problematic, since IPAM uses that ID as key to track who owns the assigned IPs.

fix:
TAPA has been improved to query NSMgr checking if it is aware of a Connection with a particular ID. If it is, the TAPA will re-use that Connection to request a NSM connection towards a particular Conduit. This shall update the connection maintained in NSM, meaning no unexpected reconnect due to duplicated connections.

Issue link

Checklist

• Purpose
  • Bug fix
  • New functionality
  • Documentation
  • Refactoring
  • CI
• Test
  • Unit test
  • E2E Test
  • Tested manually
• Introduce a breaking change
  • Yes (description required)
  • No