fix(client): #1182 filter out empty extra arguments for fortls extraArgs

[folk85]

Empty variable in the ExtraArgs list are included into the global argument list and then fortls try to parse it. Here is the simple example which reproduce the problem:

#file:./.vscode/settings.json
    "fortran.fortls.extraArgs": [
        "--max_comment_line_length=500",
        "",
        "",
        "",
        "",
        "--max_line_length=500",
    ],

The Output panel of "Modern Fortran" shows the following error:

If we filter the argument list eliminating empty arguments the problem is dissappearing:

[gnikit]

Thanks for the fix @folk85

[codecov]

Codecov Report

❌ Patch coverage is 0% with 2 lines in your changes missing coverage. Please review.
✅ Project coverage is 81.26%. Comparing base (d5c808a) to head (7fd9374).
⚠️ Report is 2 commits behind head on main.

Files with missing lines	Patch %	Lines
src/lsp/client.ts	0.00%	2 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #1261      +/-   ##
==========================================
- Coverage   81.30%   81.26%   -0.04%     
==========================================
  Files          12       12              
  Lines        2321     2322       +1     
  Branches      191      191              
==========================================
  Hits         1887     1887              
- Misses        429      430       +1     
  Partials        5        5              

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