chore: remove yy/LL/dd formatter date format

[m0nggh]

Problem

Realised that we have conflicting formats dd/LL/yy vs yy/LL/dd and it could pose as a problem when people use this format later in a delay step

Solution

Remove the yy/LL/dd datetime format

Regression test

• Check that prod doesn't have any steps that uses this date format thankfully (only 2 but both are deleted)
  Simple query:

SELECT
	*
FROM
	steps
WHERE
	key = 'dateTime'
	and parameters::text ilike '%"formatDateTimeToFormat": "yy/LL/dd"%''

[datadog-opengovsg]

Datadog Report

Branch report: chore/formatter/remove-date-option
Commit report: 6777eee
Test service: plumber

✅ 0 Failed, 687 Passed, 0 Skipped, 2m 4.5s Total Time
🔻 Test Sessions change in coverage: 1 decreased (-0.02%)

🔻 Code Coverage Decreases vs Default Branch (1)

• vitest 30.44% (-0.02%) - Details