Fix noTemplate option of ComponentTestBed and post-test code execution of ServiceTestBed

[remscodes]

• Fix noTemplate option of ComponentTestBed.
• Make sure that the post-test code for ServiceTestBed is run after the end of the test (async or not).
• Refactor error message.
• Make RxBox unsubsribe() and complete() private.

[codecov]

Codecov Report

Attention: 2 lines in your changes are missing coverage. Please review.

Comparison is base (6f34097) 96.77% compared to head (168696d) 97.68%.

Files	Patch %	Lines
...ting-tools/src/lib/common/test-bed/jasmine-done.ts	71.42%	2 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main      #48      +/-   ##
==========================================
+ Coverage   96.77%   97.68%   +0.90%     
==========================================
  Files          48       50       +2     
  Lines         248      259      +11     
  Branches       51       52       +1     
==========================================
+ Hits          240      253      +13     
+ Misses          8        6       -2     

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