Use create_sending_location_test_flags in demographic tests

[Jennit07]

Linked to #818

Please see the comment in #818 this could only be applied to the sc demographics tests. Small change to include this in those tests.

[github-actions]

@check-spelling-bot Report

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See the 📂 files view, the 📜action log, or 📝 job summary for details.

❌ Errors	Count
❌ ignored-expect-variant	13
ℹ️ no-newline-at-eof	1

See ❌ Event descriptions for more information.

Available 📚 dictionaries could cover words (expected and unrecognized) not in the 📘 dictionary

This includes both expected items (232) from .github/actions/spelling/expect.txt and unrecognized words (0)

Dictionary	Entries	Covers	Uniquely
cspell:filetypes/filetypes.txt	264	1
cspell:npm/dict/npm.txt	302	1

Consider adding them (in .github/workflows/spelling.yml) for uses: check-spelling/check-spelling@main in its with:

      with:
        extra_dictionaries:
          cspell:filetypes/filetypes.txt
          cspell:npm/dict/npm.txt

To stop checking additional dictionaries, add (in .github/workflows/spelling.yml) for uses: check-spelling/check-spelling@main in its with:

check_extra_dictionaries: ''