Remove unused code

[karthiknadig]

Closes #15717

[karrtikr]

IIRC Eric added certain display helpers that are not used currently. Please verify that we aren't removing those utils.

[codecov-io]

Codecov Report

Merging #15718 (9b1b21f) into main (e3e773a) will increase coverage by 0%.
The diff coverage is 100%.

@@           Coverage Diff           @@
##            main   #15718    +/-   ##
=======================================
  Coverage     65%      65%            
=======================================
  Files        551      551            
  Lines      26342    26112   -230     
  Branches    3802     3761    -41     
=======================================
- Hits       17235    17179    -56     
+ Misses      8378     8204   -174     
  Partials     729      729            

Impacted Files	Coverage Δ
src/client/activation/types.ts	100% <ø> (ø)
src/client/application/diagnostics/types.ts	100% <ø> (ø)
src/client/common/constants.ts	100% <ø> (ø)
src/client/common/editor.ts	9% <ø> (-1%)	⬇️
src/client/common/helpers.ts	100% <ø> (+36%)	⬆️
src/client/common/platform/errors.ts	100% <ø> (+1%)	⬆️
src/client/common/platform/types.ts	100% <ø> (ø)
...rc/client/common/process/internal/scripts/index.ts	68% <ø> (+3%)	⬆️
src/client/common/process/types.ts	100% <ø> (ø)
src/client/common/types.ts	100% <ø> (ø)
... and 22 more