Draft: fix(Conflict detection): Exclude computed internal fields from Page entity normalization

Merging !1107 (merged) increased the fragility of e2e tests. Specifically, cypress e2e 2/4 and empty-canvas.cy.js often fails due to HTTP409 response causing error overlay. This specific test uses metatag and local testing seems to implicate computed fields, specifically the metatag computed field.

This is just an attempt to see how badly BE and e2e tests would do if we were to exclude the fields that are both computed and internal when normalizing Page entities.

The idea for this came late at night while looking at EntityFieldPropSourceMatcher.php#L591 and ComponentTreeItem.php#L378, so it might be wrong way to solve this. 🫠

Testing instructions

• First step for someone to test the changes in this MR

Closes #3589076