Adding wait for button to exist

[lgrossma]

See: #4129

[codecov-commenter]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 43.92%. Comparing base (da60441) to head (de9d49e).
Report is 357 commits behind head on main.

Additional details and impacted files

@@             Coverage Diff             @@
##             main    #4281       +/-   ##
===========================================
+ Coverage   32.37%   43.92%   +11.55%     
===========================================
  Files          85       95       +10     
  Lines        6505     7699     +1194     
  Branches     1349     1647      +298     
===========================================
+ Hits         2106     3382     +1276     
+ Misses       4399     4317       -82     

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[lgrossma]

@vrubezhny This PR is response to your comments in #4129. It should provide some more stability, but even if I run the tests many times, I couldn't reproduce the fails you mentioned...

[vrubezhny]

Looks good to me. Thanks!

[vrubezhny]

@lgrossma Recently the builds/tests runs quite a lot more stably (especially Create Component tests)

From the problems I see sometimes is:

• Slow refreshing of Components Tree (is to be fixed later)
• Devfile Registry Editor items list is compared against the predefined test list of Devfile names BEFORE they actually appeared on the first search page, like in https://github.com/redhat-developer/vscode-openshift-tools/actions/runs/9814623145/job/27102500291 - ODO registry command returns all the required Devfiles, Registry Editor Search shows all 12 devfiles on the first page (when running manually), but test makes a try to check the Devfiles on the page BEFORE all of them are really shown on the first search page:

  1) Extension public-facing UI tests
       Devfile Registries
         open Devfile registry view from item's context menu and verify the content of the registry:

      AssertionError: expected [ 'Quarkus Java', '.NET 5.0', …(3) ] to be a superset of [ 'Quarkus Java', 'Django', …(7) ]
      + expected - actual

       [
         "Quarkus Java"
      -  ".NET 5.0"
      -  ".NET Core 3.1"
      -  "Universal Developer Image"
      -  "Vue"
      +  "Django"
      +  "Go Runtime"
      +  "Maven Java"
      +  "Node.js Runtime"
      +  "Open Liberty Gradle"
      +  "Open Liberty Maven"
      +  "Python"
      +  "Vert.x Java"
       ]
      
      at Context.<anonymous> (test/ui/suite/devfileRegistries.ts:129:70)
      at Generator.next (<anonymous>)
      at fulfilled (out/test/ui/suite/devfileRegistries.js:5:58)
      at processTicksAndRejections (node:internal/process/task_queues:95:5)