Apply limit to database rather than collection

[morrislaptop]

If the following conditions are true:

• The test is using DatabaseTransactions rather than RefreshDatabase;
• There is a large dataset for the table under test;
• The assertDatabaseHas assertion is being used; and
• The assertion fails

The entire table is put into memory causing allowed memory fatal errors.

This is because the limit is applied on a Collection after putting all the records in memory.

This change puts the limit on the database query so only the limited amount of records go into memory.

This avoids errors in tests for users and does not break any existing features.

[driesvints]

This seems to break the test suite. Feel free to resubmit once you've fixed the tests.

[morrislaptop]

@driesvints done with #30148, thanks!