[YUNIKORN-601] KubeClient mock does not allow failure tests

[steinsgateted]

What is this PR for?

change to NewKubeClientMock(showError bool) in order to show error.
chage to NewMockedAPIProvider(showError bool) in order to pass parameter to NewKubeClientMock(showError).
Then change each NewMockedAPIProvider() to NewMockedAPIProvider(false).

What type of PR is it?

• - Bug Fix
• - Improvement
• - Feature
• - Documentation
• - Hot Fix
• - Refactoring

Todos

• - Task

What is the Jira issue?

https://issues.apache.org/jira/projects/YUNIKORN/issues/YUNIKORN-601

How should this be tested?

Screenshots (if appropriate)

Questions:

• - The licenses files need update.
• - There is breaking changes for older versions.
• - It needs documentation.

[codecov]

Codecov Report

Merging #395 (c179ced) into master (9aca5ce) will increase coverage by 0.06%.
The diff coverage is n/a.

@@            Coverage Diff             @@
##           master     #395      +/-   ##
==========================================
+ Coverage   65.41%   65.47%   +0.06%     
==========================================
  Files          40       40              
  Lines        6314     6325      +11     
==========================================
+ Hits         4130     4141      +11     
  Misses       2023     2023              
  Partials      161      161              

Impacted Files	Coverage Δ
pkg/cache/placeholder.go	100.00% <0.00%> (ø)
pkg/cache/context.go	45.60% <0.00%> (+0.07%)	⬆️
pkg/cache/application.go	72.21% <0.00%> (+0.46%)	⬆️

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[wilfred-s]

LGTM

The change does not add new failure test, it just adds the possibility to create the client that can return a failure.
New tests should be added to also test failure cases.