[url_launcher] Added draggable property to link info.

[kristoffer-zliide]

Platform interface part of allowing use of the Link widget in lists with mouse drag enabled.

Platform interface part of #5430

Issues fixed: #102735

Pre-launch Checklist

• [x] I read the [Contributor Guide] and followed the process outlined there for submitting PRs.
• [x] I read the [Tree Hygiene] wiki page, which explains my responsibilities.
• [x] I read and followed the [relevant style guides] and ran [the auto-formatter]. (Unlike the flutter/flutter repo, the flutter/plugins repo does use dart format.)
• [x] I signed the [CLA].
• [x] The title of the PR starts with the name of the plugin surrounded by square brackets, e.g. [shared_preferences]
• [x] I listed at least one issue that this PR fixes in the description above.
• [x] I updated pubspec.yaml with an appropriate new version according to the [pub versioning philosophy], or this PR is [exempt from version changes].
• [x] I updated CHANGELOG.md to add a description of the change, [following repository CHANGELOG style].
• [x] I updated/added relevant documentation (doc comments with ///).
• [ ] I added new tests to check the change I am making, or this PR is [test-exempt].
• [ ] All existing and new tests are passing.

[flutter-dashboard[bot]]

It looks like this pull request may not have tests. Please make sure to add tests before merging. If you need an exemption to this rule, contact Hixie on the #hackers channel in Chat (don't just cc him here, he won't see it! He's on Discord!).

If you are not sure if you need tests, consider this rule of thumb: the purpose of a test is to make sure someone doesn't accidentally revert the fix. Ask yourself, is there anything in your PR that you feel it is important we not accidentally revert back to how it was before your fix?

Reviewers: Read the Tree Hygiene page and make sure this patch meets those guidelines before LGTMing.

[ditman]

Unfortunately I cannot push to this branch:

ERROR: Permission to zliide/flutter_plugins.git denied to ditman.
fatal: Could not read from remote repository.

Please make sure you have the correct access rights
and the repository exists.

[stuartmorgan]

@kristoffer-zliide Are you planning on updating this PR based on the discussion above?

[dab246]

@ditman I am using the Link widget of url_launcher in a Draggable and cannot drag it. Is there any temporary solution to this problem? Before the PR was merged.

[chibenwa]

What's the ETA of this work?

[stuartmorgan]

Thank you for your contribution. I'm going to close this PR for now since there are outstanding comments, just to get this off our PR review queue. Please don't hesitate to submit a new PR if you have the time to address the review comments. Thanks!