refactor: Deduplicate get_new_identifier

[divs4debu]

Fixes #7016

Short description of what this resolves:

Changes proposed in this pull request:

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.

[codecov]

Codecov Report

Merging #7182 into development will increase coverage by 0.08%.
The diff coverage is 93.33%.

@@               Coverage Diff               @@
##           development    #7182      +/-   ##
===============================================
+ Coverage        62.79%   62.87%   +0.08%     
===============================================
  Files              262      259       -3     
  Lines            13028    12992      -36     
===============================================
- Hits              8181     8169      -12     
+ Misses            4847     4823      -24     

Impacted Files	Coverage Δ
app/api/helpers/db.py	96.72% <83.33%> (-1.47%)	⬇️
app/api/helpers/scheduled_jobs.py	47.77% <100.00%> (ø)
app/models/event_invoice.py	95.23% <100.00%> (+1.62%)	⬆️
app/models/order.py	91.54% <100.00%> (+0.75%)	⬆️
app/api/helpers/files.py	73.71% <0.00%> (-1.29%)	⬇️
manage.py	0.00% <0.00%> (ø)
app/api/routes.py	100.00% <0.00%> (ø)
app/api/schema/settings.py	100.00% <0.00%> (ø)
app/models/module.py
app/api/modules.py
... and 9 more

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