Fixed sharing wasn't working when it is on iPad (closes #83)

[Khosbayar]

Context

Sharing was not working when user is on iPad. The root cause is because we didn't set mandatory parameter when sharing on iPad (link)

Closes #83

From the official documentation

Solution

Added sharePositionOrigin parameter when sharing X file.

Testing

Verified new changes on following devices:

• Google pixel 2xl (Android - device)
• Google pixel 5 (Android - simulator)
• iPhone 14 Pro (iOS - simulator)
• iPad 10th gen (iOS - device)

[ndahlquist]

Beautiful! That context thing is some deep Flutter shit, I wish I fully understood why they needed to use a Builder there...