fix(database): schema editor _id, createdAt, updatedAt field constraints

[kon14]

Updates the schema editor so that non-editable fields' constraints are properly displayed.
Also recolors disabled fields' delete button (previously red despite being disabled).

Ideally we wouldn't be sending back _id, createdAt and updatedAt at all as the backend overrides these anyway, but the codebase is a mess, so yeah.

What kind of change does this PR introduce? (check at least one)

• Bugfix
• Feature
• Code style update
• Refactor
• Build-related changes
• Other, please describe:

Does this PR introduce a breaking change? (check one)

• Yes
• No

If yes, please describe the impact and migration path for existing applications:

The PR fulfills these requirements:

• It's submitted to the main branch
• When resolving a specific issue, it's referenced in the PR's title (e.g. fix #xxx, where "xxx" is the issue number)