Attempting to Save+Continue a proposal with a title > 250 characters results in a meaningless error

[georgeflecknell]

• Who does this affect?
  All proposal submitters
• What needs to change?
  Error messages need to indicate source of actual error and not mislead. Currently the error warns that the abstract is too long as it exceeds 175 characters. The abstract limit hasn't actually been exceeded, it's the title and the limit of that is 250 words.
  This was tested with a 300 characters (43 words) input and the issue replicated:

• What events does this affect?
  All proposal submission

• Why does it need to change?
  Current validation produces misleading errors, lowering user confidence and confusing them

• Who requested it and when?
  Noticed by a submitter during isis 2026_2 proposal call.