Format Solr schema.xml using update-fields.sh on Linux

[pdurbin]

What this PR does / why we need it:

We need a consistent way to format our Solr schema.xml file. If we have some people using Mac and others using Linux, the git diff output will be harder to read due to sorting differences.

Which issue(s) this PR closes:

• Closes The Solr schema.xml file should be generated programmatically using update-fields.sh #11023

Special notes for your reviewer:

I used this procedure to update schema.xml in the following PR (which has already been merged):

• feat: index numerical and date fields in Solr with appropriate types + more targeted search result highlighting #10887

Suggestions on how to test this:

Try the steps documented in this PR.

Does this PR introduce a user interface change? If mockups are available, please link/include them here:

No.

Is there a release notes update needed for this change?:

No, this is dev territory.

Additional documentation:

None.