Update task: Number format

[nicolemjohnson]

edu.hm.cs.ma.todoguru_issue_93e37c660fe0d6301b36eeab7443acda_crash_session_5F005F40023B000137B949C0AF9BEB1E_DNE_0_v2.log
Firebase Crash:

When updating the task, number is not correctly formated. There needs to be a check on whether the new value is the correct format for the database.

Acceptance Criteria: No more firebase crashes for NumberFormatException when updating a task

[nicolemjohnson]

[nicolemjohnson]