fix(obligation): stop persisting tab chars in obligation text (#3214)

[Flamki]

Fixes: #3214

This PR focuses on the remaining reproducible part of the issue: tab characters (\t) getting persisted in obligation text.

What changed

• Added obligation text normalization in ThriftValidate.prepareTodo(...).
• Tabs are converted to regular spaces before persistence.
• Added unit test coverage in ThriftValidateTest to prevent regressions.

Why this approach

• prepareTodo(...) is used by obligation add/update flows, so this keeps behavior consistent across write paths.
• It is a minimal, targeted fix and avoids touching unrelated obligation rendering logic.

Validation

• Ran locally:
  • mvn -pl :datahandler -Dtest=ThriftValidateTest -Dbase.deploy.dir=. test
  • mvn -pl :datahandler -DskipTests -Dbase.deploy.dir=. compile
• Result: both commands passed.

Notes

• The HTML entity part (") appears already handled by current XSS sanitization on main.
• This PR addresses the tab-character persistence part of Admin: Obligations: DB stores un-necessary HTML entities and tab characters on adding certain Obligations. #3214.