Fixup: use fast queries for fields shared between albums and items tables

[snejus]

I surprisingly found that many queries for fields that exist in the database are 'slow'. Querying items with month:0 used a slow query while title:0 used a fast one.

I found the mistake in the logic: the field existence in the db check was done after prepending the table name to the field. This meant that the logic wrongly checked e.g. items.field instead of field.

This commit fixes the above and renames the variables for more clarity.

[github-actions[bot]]

Thank you for the PR! The changelog has not been updated, so here is a friendly reminder to check if you need to add an entry.

[Serene-Arc]

Merge when ready, unless you want another review @snejus

[Serene-Arc]

btw again, great catch. It took me like 5 different readings to get what changed in that code lol

[snejus]

btw again, great catch. It took me like 5 different readings to get what changed in that code lol

Sounds like the code should be improved regarding its readability 😆