Add ignore_expected_loganalyzer_exceptions fixture to test_lldp_entry_table_after_lldp_restart

[sakshamkhurana21]

Description of PR

Fixes intermittent teardown failures in lldp.test_lldp_syncd::test_lldp_entry_table_after_lldp_restart caused by transient monit 'routeCheck' status failed ERR lines in syslog after the LLDP container is restarted.

2026 Jun  9 05:41:07.331542 vlab-03 ERR monit[91284]: 'routeCheck' status failed (255) -- Failure results: {{#012    "": {#012        "Unaccounted_ROUTE_ENTRY_TABLE_entries": [#012            "10.0.0.38/31",#012            "100.1.0.21/32",#012            "192.168.32.0/25",#012            "192.168.32.128/25",#012            "192.217.224.0/25",#012            "20c0:a820:0:80::/64",#012            "20c0:a820::/64",#012            "fc00::4c/126"#012        ]#012    }#012}}#012Failed. Look at reported mismatches above#012add: {#012    "": []#012}#012del: {#012    "": []#012}

This is a one-line fix: the test was missing the ignore_expected_loganalyzer_exceptions fixture in its signature, so the existing ignore-regex (added in PR #15258) was never installed for this test. Its sibling tests (test_lldp_entry_table_after_cont_flap, test_lldp_entry_table_after_all_batched_flap) already declare the same fixture and pass cleanly.

Summary:
Fixes # (issue)

Type of change

• Bug fix
• Testbed and Framework(new/improvement)
• New Test case
  • Skipped for non-supported platforms
• Test case improvement

Back port request

• 202311
• 202405
• 202411
• 202505
• 202511
• 202512
• 202605

Approach

What is the motivation for this PR?

test_lldp_entry_table_after_lldp_restart has been flaking at ~12% on vlab-03 for weeks. The test body itself passes — the failure happens at teardown when loganalyzer flags an ERRmonit[...]: 'routeCheck' status failed line that is emitted momentarily while LLDP is being restarted (systemctl restart lldp). Routes briefly fail their consistency check while LLDPrepopulates neighbor info, then recover on the next monit poll.

How did you do it?

How did you verify/test it?

Any platform specific information?

N/a

Supported testbed topology if it's a new test case?

N/a

Documentation

N/a

[mssonicbld]

/azp run

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Azure Pipelines successfully started running 1 pipeline(s).

[StormLiangMS]

LGTM