refactor: update request/limit checks against zero

Description

This MR unifies how we are checking if the resource request/limits are set (properly). When we were comparing the value with 0, we were losing the ability to define values like 500m for CPU. This wasn't intentional and indeed a bug. In this MR, we are removing the comparison to allow using a string or float for defining requests/limits.

Supporting information

• https://tasks.opencraft.com/browse/SE-5972
• https://chat.opencraft.com/opencraft/pl/6mx6w4zjotftumwawk66zqxxny

Testing instructions

Steps to test the changes:

1. Proofread
2. (optional) set autoscaling using 100m instead of 0.1

Dependencies

N/A

Screenshots

N/A

Checklist

If any of the items below is not applicable, do not remove them, but put a check in it.

• Git commit history is clean
• Git commits are following conventional-commit practices
• Unit tests are added/updated
• Documentation is added/updated

Additional context

N/A