Fixes#11998
Avoids UI lockups by removing several unnecessary mutex blocks and avoiding redundant key detection calls.
Detect Yubikeys dynamically when challenging:
Prevents issue where correct key cannot be found if the internal state was reset prior to saving
This can occur if a user has multiple tabs open and multiple keys connected. Then switches to a locked tab without their DB key inserted which resets detection state.
Side Benefit - ensures proper cascade between USB and PC/SC interfaces so users can switch between the two modes seamlessly.
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