FIX: breaking datetime in edit mode

Summary

Fix for https://gitlab.com/linkahead/linkahead-webui/-/issues/239

Focus

1. Introduce a trim to deal with whitespaces
2. add subseconds to tag attribute to preserve it.

This is far from perfect but substantially improves status quo: First of all we do no longer destroy timestamps simply by using the edit mode (and without even touching the timestamp). Subsecond resolution can still not be changed, but at least it is preserved!

Do we need to deal with time zones as well?

Test Environment

• pipelines
• manually test:
  1. click Edit and then Save on an entity with a timestamp with sub seconds. Check that it did not change
  2. do the same for list properties

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