Improves KeYSelectionModel usage and removed RuleAppListener from ProofTreeView

[unp1]

Factored these changes out from PR #3335 to keep the PRs more focused

Overall:

• Reduce unnecessary event propagation and handling during automode
• TaskTree unregisters properly during automode
• Remove GUI specific functionality from KeYMediator (DelayCut behavior) to the corresponding action object.

KeYSelectionModel

• Consistent state of KeYMediator and its selection model
• Reduction in duplicate selection events
• Clearer flow of information

ProofTreeView:

• Remove RuleAppListener -- RuleAppListener should only be used by prover internal entitied that are required for the proof search. Others should not use it or listen for autoModeStarted events and unregister. ProofTreeView did not need to be a rule app listener, so this could be removed completely.

Additional synchronizations to fix that quick random clicks on start/stop caused exceptions and/or deadlocks.

[codecov[bot]]

Codecov Report

Merging #3341 (75aff1f) into main (295186f) will increase coverage by 0.00%. The diff coverage is 80.95%.

@@            Coverage Diff            @@
##               main    #3341   +/-   ##
=========================================
  Coverage     37.84%   37.84%           
  Complexity    16895    16895           
=========================================
  Files          2054     2054           
  Lines        125488   125490    +2     
  Branches      21227    21227           
=========================================
+ Hits          47493    47495    +2     
  Misses        72142    72142           
  Partials       5853     5853           

Files	Coverage Δ
.../de/uka/ilkd/key/control/AbstractProofControl.java	9.09% <ø> (ø)
...ka/ilkd/key/proof/reference/ReferenceSearcher.java	83.56% <ø> (ø)
...ilkd/key/control/AbstractUserInterfaceControl.java	79.01% <89.47%> (+0.53%)	:arrow_up:
...a/de/uka/ilkd/key/macros/SequentialProofMacro.java	6.25% <0.00%> (ø)

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[Drodt]

I tested it on my machine and could not produce any deadlocks.

[unp1]

This PR is from my point of view now stable and complete