Fix handle leak for killed worker checker

[cmdcolin]

The current code for checking if a worker was killed would progressively create more watchers over time because the resolve was never called. I mistakenly thought that Promise.race might kill the watcher promise

This was found because I saw the code freeze, and clicking the pause tab in the source debugger always ended up at the worker=='killed' line which seemed odd, and console.logging around this line indicated that it could be called thousands of times a second

[codecov]

Codecov Report

Merging #2197 (2442de6) into main (ba45e95) will increase coverage by 0.00%.
The diff coverage is 88.88%.

@@           Coverage Diff           @@
##             main    #2197   +/-   ##
=======================================
  Coverage   62.71%   62.72%           
=======================================
  Files         484      484           
  Lines       22641    22646    +5     
  Branches     5141     5142    +1     
=======================================
+ Hits        14200    14205    +5     
  Misses       8171     8171           
  Partials      270      270           

Impacted Files	Coverage Δ
packages/core/rpc/BaseRpcDriver.ts	84.90% <88.88%> (-0.25%)	⬇️
...r-view/src/BaseChordDisplay/components/Loading.tsx	100.00% <0.00%> (+5.00%)	⬆️

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