[LW] Add some more logging

[Jolyon-S]

Goals (and why):
==COMMIT_MSG==
Add additional logging when the lock watch cache falls back due to validation failures
==COMMIT_MSG==

Implementation Description (bullets):

• add a stacktrace for when the validation fails
• add a logline for the fallback (which can be called by itself instead of by catching an exception, and thus there isn't always a guaranteed logline present currently).

Concerns (what feedback would you like?):
While we're at it, anything else we should probably add?

Priority (whenever / two weeks / yesterday):
ASAP

[changelog-app]

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Type

• Feature
• Improvement
• Fix
• Break
• Deprecation
• Manual task
• Migration

Description

Add additional logging when the lock watch cache falls back due to validation failures

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[gmaretic]

gift that keeps on giving

[svc-autorelease]

Released 0.519.0