fix(db): Stop writing unused dbport to config at install time

[joshtrichards]

• Resolves: #

Summary

We already have handling for specifying a port at install time or later on (which work just fine). Yet we write out a bogus parameter dbport to the initial config.

This value is neither supported nor used (even at install time). Yet we save this bogus parameter in the initial config. Since it's in the config, people end up assuming it does something and wondering why it doesn't work.

It either ends up being:

        "dbport": "",

Or, if a specific port was explicitly specified via maintenance:install --database-port than that port ends up there. It gets populated with the correct value, but it's still not actually used so 🤷

        "dbport": "3306",

Let's not write it to the config at install time since it's a no-op and avoid all this confusion.

Additional historical context:

• mysql port syntax in config #15560
• d367318
• Fix occ maintenance:install database connect failure #19303

TODO

• ...

Checklist

• Code is properly formatted
• Sign-off message is added to all commits
• Tests (unit, integration, api and/or acceptance) are included
• Screenshots before/after for front-end changes
• Documentation (manuals or wiki) has been updated or is not required
• Backports requested where applicable (ex: critical bugfixes)