feat: added prop to allow target's default behaviour

[pawanbangar]

added prop allowTargetInteraction which will allow target's default behaviour

Description

Currently we are not allowed to make target interactive, because positioned widget is drawn on top of overlay, this PR will remove that positioned widget, then user won't able to use onClick on target, this is not a breaking change allowTargetInteraction will handle this via removing that widget if passed as true

Checklist

• [x] The title of my PR starts with a Conventional Commit prefix (fix:, feat:, docs: etc).
• [x] I have followed the Contributor Guide when preparing my PR.
• [x] I have updated/added tests for ALL new/updated/fixed functionality.
• [x] I have updated/added relevant documentation in docs and added dartdoc comments with ///.
• [ ] I have updated/added relevant examples in examples or docs.

Breaking Change?

• [ ] Yes, this PR is a breaking change.
• [x] No, this PR is not a breaking change.

Related Issues

Closes https://github.com/SimformSolutionsPvtLtd/flutter_showcaseview/issues/467#issue-2451008787 and https://github.com/SimformSolutionsPvtLtd/flutter_showcaseview/issues/465#issue-2435049628