refactor(datetime): simpler way of accounting for time zone offsets in getToday

[liamdebeasi]

Pull request checklist

Please check if your PR fulfills the following requirements:

• Tests for the changes have been added (for bug fixes / features)
• Docs have been reviewed and added / updated if needed (for bug fixes / features)
• Build (npm run build) was run locally and any changes were pushed
• Lint (npm run lint) has passed locally and any fixes were made for failures

Pull request type

Please check the type of change your PR introduces:

• Bugfix
• Feature
• Code style update (formatting, renaming)
• Refactoring (no functional changes, no api changes)
• Build related changes
• Documentation content changes
• Other (please describe):

What is the current behavior?

• The current fix for fix(datetime): account for 30 and 45 minute timezones when getting current date #25120 works, but it is overly complex: 96b2003
• The reason is that we get the time zone offset in minutes, yet we convert to hours and then back to minutes. We should just be using the minutes value directly.

What is the new behavior?

• Simplifies getToday by just passing the current minutes + the time zone offset to setMinutes.

Does this introduce a breaking change?

• Yes
• No

Other information