Bugfix 2428 python csv input

[hsoh-u]

Expected Differences

The problem did not happen at this branch, but happened at the develop branch. The fix is making sure that the global attribute "use_var_id" should be processed on reading NetCDF input. Some old MET point observation NetCDF files has "false" at "use_var_id", or no "use_var_id" global attribute.

• Do these changes introduce new tools, command line arguments, or configuration file options? [No]
  
  If yes, please describe:
  

• Do these changes modify the structure of existing or add new output data types (e.g. statistic line types or NetCDF variables)? [No]
  
  If yes, please describe:
  

Pull Request Testing

• Describe testing already performed for these changes:
  

I was not find the input which failed on reading. But it's safe to modify the code.
The command will be

python3 share/met/wrappers/read_tmp_point_nc.py unit_test_output/ascii2nc/gauge_2012041012_24hr.nc

The error message was(if use_var_id attribute is not processed correctly, but I did not reproduce this)

python:  ==PYTHON_ERROR== obs_var_table is empty (string)

• Recommend testing for the reviewer(s) to perform, including the location of input datasets, and any additional instructions:
  

• Do these changes include sufficient documentation updates, ensuring that no errors or warnings exist in the build of the documentation? [No]

• Do these changes include sufficient testing updates? [No]

• Will this PR result in changes to the test suite? [Yes or No]
  
  If yes, describe the new output and/or changes to the existing output:
  

• Please complete this pull request review by [Fill in date].
  

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[JohnHalleyGotway]

I approve of these changes.

I diffed the contents of these 2 python scripts between the bugfix_2428_python_csv_input, main_v11.0, and develop branches. I see that you're using this PR to port over the logic from develop into main_v11.0. And those changes were already reviewed/approved for develop by @DanielAdriaansen in PR #2462.