Multi-asic fixes for lldp/test_lldp_syncd.py

[arista-nwolfe]

Description of PR

Various multi-asic fixes in lldp/test_lldp_syncd.py

• Fix helper functions db_instance, get_lldp_entry_keys, get_lldp_entry_content, get_lldpctl_output to query both namespaces

test_lldp_entry_table_after_flap

• Ignore routeCheck log errors as this test flaps ports and churns routes ignore_expected_loganalyzer_exceptions
• Don't skip the test if it finds eth0 port, just continue
• Add namespace to config interface commands
• Increase delay from 5s to 10s as verify_lldp_entry was seeing the stale LLDP_ENTRY from before link flap and returning True

test_lldp_entry_table_after_lldp_restart

• Query the per-namespace lldp docker when available

test_lldp_entry_table_after_reboot

• wait until check_intf_up_ports=True when rebooting, otherwise the LLDP_ENTRY may flap when the ports come up

Summary:
Fixes #15256

Type of change

• Bug fix
• Testbed and Framework(new/improvement)
• Test case(new/improvement)

Back port request

• 202012
• 202205
• 202305
• 202311
• 202405

[mssonicbld]

The pre-commit check detected issues in the files touched by this pull request.
The pre-commit check is a mandatory check, please fix detected issues.

Detailed pre-commit check results:
trim trailing whitespace.................................................Passed
fix end of files.........................................................Passed
check yaml...........................................(no files to check)Skipped
check for added large files..............................................Passed
check python ast.........................................................Passed
flake8...................................................................Failed
- hook id: flake8
- exit code: 1

tests/lldp/test_lldp_syncd.py:19:1: E302 expected 2 blank lines, found 1
tests/lldp/test_lldp_syncd.py:31:1: E302 expected 2 blank lines, found 1
tests/lldp/test_lldp_syncd.py:50:1: E302 expected 2 blank lines, found 1
tests/lldp/test_lldp_syncd.py:57:1: E302 expected 2 blank lines, found 1

flake8...............................................(no files to check)Skipped
check conditional mark sort..........................(no files to check)Skipped

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