[Bug]: test_startup_tsa_tsb_service.py doesn't check bgp status before checking if routes are propogated

[vperumal]

Issue Description

In multiple instances of the test, the testcase doesn't check if the bgp sessions are up before checking if only loopback routes are propogated or all the routes are propogated. This causes testcase failures and the failure points in the wrong direction.

The test also doesn't check the state of system after the checking for interface, critical process status, it assumes that it is either normal or in maintenance mode causing the testcase to fail for the wrong reason.

Results you see

Test case failures for the wrong reason

Results you expected to see

Test case should check the state of the system right before it checks for the functionality validation

Is it platform specific

generic

Relevant log output

No response

Output of show version

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Attach files (if any)

No response

[vperumal]

FYI @abdosi @anamehra - @abdosi please assign the issue to me - I will create a PR for it.