Fix create serverless function view

[datho7561]

• Split out the "invoke serverless function" webview from the "create serverless function" webview
• For "create serverless function" and "invoke serverless function", wait on receiving a message from the webview before sending data to it
• Fixing theming in the "invoke serverless function" webview

Fixes #4092

[datho7561]

The root cause for this bug is the same as for the Helm Chart browser: we need confirmation from the webview that it's ready before we can start sending data to it.

[codecov-commenter]

Codecov Report

Attention: Patch coverage is 21.47651% with 117 lines in your changes are missing coverage. Please review.

Project coverage is 44.09%. Comparing base (da60441) to head (e030bef).
Report is 254 commits behind head on main.

Files	Patch %	Lines
...verless-function/invokeServerlessFunctionLoader.ts	22.36%	59 Missing ⚠️
...ew/serverless-function/serverlessFunctionLoader.ts	18.84%	56 Missing ⚠️
src/serverlessFunction/view.ts	50.00%	1 Missing ⚠️
src/webview/common-ext/utils.ts	50.00%	1 Missing ⚠️

Additional details and impacted files

@@             Coverage Diff             @@
##             main    #4160       +/-   ##
===========================================
+ Coverage   32.37%   44.09%   +11.72%     
===========================================
  Files          85       91        +6     
  Lines        6505     7291      +786     
  Branches     1349     1540      +191     
===========================================
+ Hits         2106     3215     +1109     
+ Misses       4399     4076      -323     

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[msivasubramaniaan]

Lgtm

[vrubezhny]

Looks good to me. Thanks!

Serverless Function Create and Invoke views work fine for me on Linux