Clean up EntitiesRepository API

[seadowg]

Closes #6566
Blocked by #6601
Blocked by #6619

This updates the delete method as described in the issue, and also removes methods we're no longer using (like getAllByProperty).

Why is this the best possible solution? Were any other approaches considered?

Not much to discuss here really! The only thing I'd point out is that I left in the (currently failing) tests for #6615 as that will make working on that issue easier when we get to it.

How does this change affect users? Describe intentional changes to behavior and behavior that could have accidentally been affected by code changes. In other words, what are the regression risks?

There's some risk to follow up and update entity forms as this messes with some of the code we use for filtering.

Before submitting this PR, please make sure you have:

• added or modified tests for any new or changed behavior
• run ./gradlew connectedAndroidTest (or ./gradlew testLab) and confirmed all checks still pass
• added a comment above any new strings describing it for translators
• added any new strings with date formatting to DateFormatsTest
• verified that any code or assets from external sources are properly credited in comments and/or in the about file.
• verified that any new UI elements use theme colors. UI Components Style guidelines

[dbemke]

Tested with Success!

Verified on a device with Android 10

Verified cases:

• registration, update and follow up forms
• deleting entities
• new versions of forms. deleting blank forms and redownloading when entities are deleted
• deleting entities when there's a draft and finalized version of an update forms
• deleting entities, adding properties in forms with a dataset with special character
• entities forms with filtering

[WKobus]

Tested with success

Verified on device with Android 15