dashboard: unaligned input containers in additional headers

To Reproduce Steps to reproduce the behavior:

1. Go to Event triggers
2. Click on New event trigger
3. Scroll down to Additional headers
4. See error

Expected behavior Input containers should be horizontally aligned

Screenshots

Follow-up: alignment in similar dashboard grids

PR #4601 fixes the original Additional Headers alignment issue. The fix covers event triggers, cron triggers, one-offs and Actions.

A source code review found 12 possible locations with the same issue:

UI area	Remaining problem
Event query parameters and form-urlencoded payloads	Colon/delete buttons retain the old padding offsets
Remote-schema relationship mappings	Validation errors displace adjacent selectors/actions
Run ports	Port errors lower the Publish switch
Run storage	First-row delete button aligns with labels rather than inputs
AI arguments	Missing Type lowers Required/delete controls
Metrics email, PagerDuty and webhook forms	Errors displace delete buttons or adjacent selectors
Database allowed CIDRs	Delete buttons retain an unnecessary top margin
Rate limits	Errors lower unit selectors and captions