fix: drop useless mutex cs_llmq_vbc to avoid deadlock

[knst]

Issue being fixed or feature implemented

Missing changes in #5736
The prior backport of bitcoin#19438 has been needed to this particular changes: drop the mutex cs_llmq_vbc.

This mutex can potentially cause deadlock such as:

'cs_dip3list' in qt/masternodelist.cpp:135 (TRY) (in thread 'main')
 (2) 'cs_llmq_vbc' in llmq/utils.cpp:704 (in thread 'main')
 'm_mutex' in versionbits.cpp:253 (in thread 'main')
 (1) 'cs_main' in node/blockstorage.cpp:77 (in thread 'main')
Current lock order is:
 'cs_Shutdown' in init.cpp:220 (TRY) (in thread 'shutoff')
 (1) 'cs_main' in init.cpp:328 (in thread 'shutoff')
 (2) 'llmq::cs_llmq_vbc' in llmq/context.cpp:64 (in thread 'shutoff')

Assertion failed: detected inconsistent lock order for 'llmq::cs_llmq_vbc' in llmq/context.cpp:64 (in thread 'shutoff'), details in debug log.

What was done?

Drop cs_llmq_vbc mutex from llmq/utils

How Has This Been Tested?

Re-started app several times -> no other deadlock happens.

Breaking Changes

N/A

Checklist:

• I have performed a self-review of my own code
• I have commented my code, particularly in hard-to-understand areas
• I have added or updated relevant unit/integration/functional/e2e tests
• I have made corresponding changes to the documentation
• I have assigned this pull request to a milestone

[UdjinM6]

utACK

smth isn't right, dynamic_activation_thresholds_tests failed

[UdjinM6]

utACK

[PastaPastaPasta]

utACK for squash merge