migrate integration_test to flutter sdk

[alexbatalov]

Description

Update integration_test to Flutter SDK.

Related Issues

#465

Checklist

Before you create this PR confirm that it meets all requirements listed below by checking the relevant checkboxes ([x]).
This will ensure a smooth and quick review process. Updating the pubspec.yaml and changelogs is not required.

• I read the Contributor Guide and followed the process outlined there for submitting PRs.
• My PR includes unit or integration tests for all changed/updated/fixed behaviors (See Contributor Guide).
• All existing and new tests are passing.
• I updated/added relevant documentation (doc comments with ///).
• The analyzer (flutter analyze) does not report any problems on my PR.
• I read and followed the Flutter Style Guide.
• I am willing to follow-up on review comments in a timely manner.

Breaking Change

Does your PR require plugin users to manually update their apps to accommodate your change?

• Yes, this is a breaking change (please indicate a breaking change in CHANGELOG.md and increment major revision).
• No, this is not a breaking change.

[juliansteenbakker]

This is blocking #442, and also preventing the CI pipeline from upgrading from flutter-version: "2.2.1" to a recent version like 2.5.1. Can this be merged?

[mhadaily]

@alexbatalov great PR. thank you. Can you just add a changelog and bump a patch version on all of these plugins? I'll merge and release right away.

[mhadaily]

I added version and changelog

LGTM