fix: remove pending from default invoice status

[uds5501]

Fixes #6368

Changes proposed in this pull request:

• set default value of event invoice objects to "due"

Checklist

• I have read the Contribution & Best practices Guide and my PR follows them.
• My branch is up-to-date with the Upstream development branch.
• The unit tests pass locally with my changes
• I have added tests that prove my fix is effective or that my feature works
• I have added necessary documentation (if appropriate)

• All the functions created/modified in this PR contain relevant docstrings.

[iamareebjamal]

Shouldn't you also write a migration for existing ones with pending status? And also for new ones with default status

[shreyanshdwivedi]

I think currently the event invoice not completely in function so maybe they are not in db too
@uds5501 please fix travis

[uds5501]

@iamareebjamal I have included the migration, please review now

[codecov]

Codecov Report

Merging #6369 into development will not change coverage.
The diff coverage is 0%.

@@             Coverage Diff              @@
##           development    #6369   +/-   ##
============================================
  Coverage        65.29%   65.29%           
============================================
  Files              287      287           
  Lines            14775    14775           
============================================
  Hits              9647     9647           
  Misses            5128     5128

Impacted Files	Coverage Δ
app/models/event_invoice.py	57.53% <0%> (ø)	⬆️

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[mrsaicharan1]

I think this migration would do. Did you test it out by running it locally though?

[uds5501]

@mrsaicharan1 yes, tested it locally, it's working