[Data collection] Prompt data collectors to agree to data sharing terms

[jcqli]

Related to google/ground-platform#1856

Need to show this data sharing agreement in the app

[gino-m]

Detailed FR:

• The first time "Collect data" is tapped for a particular survey, the terms set by the survey organizer will be shown.
• The user must accept these terms before they can begin collecting data. If they don't agree, they'll be returned to the map without being able to provide data.
• The terms cannot be revoked once granted.

@rawbzz @amegantz @vittorino FYI