Put back the runMagicCommands but deprecate it

[rchiodo]

For #7294

Support old runMagicCommands and deprecate the setting

Fix #7370 - Errors make the run button go away

Also fix a number of issues found while testing

• Text output has a weird border on the right after the change for no horizontal scrolling
• Native editors can flash weirdly

[codecov-io]

Codecov Report

Merging #7382 into master will increase coverage by 0.65%.
The diff coverage is 0%.

@@            Coverage Diff             @@
##           master    #7382      +/-   ##
==========================================
+ Coverage    57.8%   58.45%   +0.65%     
==========================================
  Files         493      493              
  Lines       21396    21750     +354     
  Branches     3481     3487       +6     
==========================================
+ Hits        12367    12715     +348     
- Misses       8246     8257      +11     
+ Partials      783      778       -5

Impacted Files	Coverage Δ
src/client/common/types.ts	100% <ø> (ø)	⬆️
src/client/datascience/jupyter/jupyterNotebook.ts	6.01% <0%> (-0.04%)	⬇️
.../datascience/interactive-common/interactiveBase.ts	6.41% <0%> (ø)	⬆️
src/client/common/logger.ts	68.55% <0%> (-4.41%)	⬇️
...t/datascience/jupyter/jupyterDataRateLimitError.ts	100% <0%> (ø)	⬆️
src/client/formatters/serviceRegistry.ts	100% <0%> (ø)	⬆️
...lient/datascience/jupyter/jupyterSelfCertsError.ts	100% <0%> (ø)	⬆️
src/client/debugger/extension/serviceRegistry.ts	100% <0%> (ø)	⬆️
src/client/common/variables/serviceRegistry.ts	100% <0%> (ø)	⬆️
src/client/common/process/serviceRegistry.ts	100% <0%> (ø)	⬆️
... and 28 more

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