Agreements: Edit/New: Remove manual formatting of dates

Dates formats in the Preview and Edit panes sometimes do not match. In both panes Stripes uses the tenant's locale to dictate the correct date format to apply. For some dates in the Edit pane this format is being overridden. All dates need to be checked and any manual setting of the date formats should be removed.

Date fields in the Agreements Edit pane which need checking:

Agreement periods:
1. Start date
2. End date
3. Cancellation deadline

Agreement lines:
4. Active from
5: Active to

Agreement lines > Custom coverage
6. Start date
7. End date

Tests which set dates will need to be updated.