tests: Add additional wait tim to test_bgp_gr_functionality_topo2-3.py

[donaldsharp]

This test is testing out GR, but is expecting routes to have been received from several routers down the line by the time the EOR has been received on the router under test. This is not a guaranteed order of events. So give the test a bit more time to see if things stabilize.

[greptile-apps]

Greptile Overview

Greptile Summary

This PR increases the retry timeout for BGP RIB route verification in a graceful restart test scenario. The change specifically targets verification of routes from r2 reaching r6 via r1 after graceful restart, extending the wait time from the default 30 seconds to 60 seconds.

The modification addresses a race condition where:

• The test waits for EOR (End-of-RIB) messages to be received on r1 after BGP daemon restart
• However, EOR receipt on r1 doesn't guarantee that routes have propagated through the topology (r1 → r6) yet
• Under load, the propagation of routes from r2 through r1 to r6 can take longer than the default 30-second timeout

The fix properly uses the retry_timeout parameter supported by the @retry decorator on verify_bgp_rib(), and includes a clear comment explaining why the extended timeout is needed for this specific check.

Confidence Score: 5/5

• This PR is safe to merge with minimal risk
• The change is a simple, well-justified test timeout adjustment that addresses a documented race condition in the BGP graceful restart test. The modification uses the proper API (retry_timeout parameter), includes explanatory comments, and only affects test stability without changing production code or test logic.
• No files require special attention

Important Files Changed

Filename	Overview
tests/topotests/bgp_gr_functionality_topo2/test_bgp_gr_functionality_topo2-3.py	Increased retry timeout from 30s to 60s for BGP RIB verification after graceful restart to handle delayed route propagation