[chore][envoy discovery] Extend integration test timeout

[crobert-1]

Description:

This test is flaky in GitHub CI and when run locally. Successful runs often take 20+ seconds, which gets close to the timeout as it is. Other discovery tests have a timeout of 1 or 2 minutes, so this update simple aligns this test with others.

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 34.45%. Comparing base (4a5ec07) to head (bcdc1bb).
Report is 3 commits behind head on main.

❗ There is a different number of reports uploaded between BASE (4a5ec07) and HEAD (bcdc1bb). Click for more details.

HEAD has 4 uploads less than BASE

Flag	BASE (4a5ec07)	HEAD (bcdc1bb)
	35	31

Additional details and impacted files

@@             Coverage Diff             @@
##             main    #6180       +/-   ##
===========================================
- Coverage   44.49%   34.45%   -10.04%     
===========================================
  Files         391      390        -1     
  Lines       27034    27014       -20     
===========================================
- Hits        12029     9308     -2721     
- Misses      14165    17083     +2918     
+ Partials      840      623      -217     

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