🐛 [cloud_firestore] Expose VectorValue

[jellynoone]

What feature would you like to see?

Support for VectorValue has landed in native client libraries:

Web Available since 10.13

• https://github.com/firebase/firebase-js-sdk/releases/tag/firebase%4010.13.0
• https://github.com/firebase/firebase-js-sdk/pull/8215
• https://firebase.google.com/support/release-notes/js#cloud-firestore

iOS Available since: 11.1.0

• https://github.com/firebase/firebase-ios-sdk/releases/tag/11.1.0
• https://github.com/firebase/firebase-ios-sdk/pull/13404
• https://firebase.google.com/support/release-notes/ios#cloud-firestore

Android Available since: 33.2.0

• https://firebase.google.com/support/release-notes/android#firestore_v25-1-0
• https://github.com/firebase/firebase-android-sdk/pull/6154