Ensure that get_latest will call get on a parameter

[jenshnielsen]

If the parameter has never been captured it seems like get_latest should also call get

This is draft due to the missing tests

[codecov]

Codecov Report

Merging #1751 into master will increase coverage by 0.02%.
The diff coverage is 93.33%.

@@            Coverage Diff             @@
##           master    #1751      +/-   ##
==========================================
+ Coverage    67.5%   67.52%   +0.02%     
==========================================
  Files         146      146              
  Lines       18320    18327       +7     
==========================================
+ Hits        12366    12376      +10     
+ Misses       5954     5951       -3

[jenshnielsen]

Todo

• Test that get is called / not called when ts is not set / set
• Test that error is raised when max_val_age is not None and get is not set
• Test that get_latest raises when get is false and set / initial value is not called
• Test that get_latest does not raise when get is false but set / initial value has been called

[jenshnielsen]

I uncovered a bug where max_val_age is never used in Parameter. Fixed and test added

[jenshnielsen]

@QCoDeS/core this is ready for review