Remove temperature_measured_at field

[sainak]

https://github.com/coronasafe/care_fe/blob/ee15f6546d01416a64a408da63b7a811da89e93a/src/Components/Facility/Consultations/DailyRounds/VirtualNursingAssistantLogUpdateCard.tsx#L34-L55
https://github.com/coronasafe/care_fe/blob/ee15f6546d01416a64a408da63b7a811da89e93a/src/Components/Patient/models.tsx#L312
https://github.com/coronasafe/care/blob/a2052f2f4a0384be57555eb2cffda4e47e1cbe54/care/facility/models/daily_round.py#L142

• remove the field from frontend
• remove the field from backend
• update migrations