[META] Update PHPDocs to reflect reality

Problem/Motivation

Spinoff from 📌 UserInterface::id(), AccountInterface::id() should return int to match typehints Needs work

Core has locations where the PHPDocs conflict with reality of usage.Examples are indicating return INT when a STRING is returned.

This is especially likely to occur when casting from the database layer.

Steps to reproduce

Proposed resolution

Update PHPDocs as necessary to match reality of usage, Especially in cases where where PHPDocs conflict with actual usage.

Remaining tasks

User interface changes

N/A

API changes

TBD, see child issues.

Data model changes

TBD

Release notes snippet

TBD