Test: Add unit & widget tests for save_page_dialog.dart

[GitMasterJatin]

What kind of change does this PR introduce?

• Added unit & widget tests for save_page_dialog.dart.

Issue Number:

• Fixes Add unit & widget tests for save_page_dialog.dart #146

Summary

• Added tests to increase code coverage.

Snapshots/Videos:

Does this PR introduce a breaking change?

• No

Have you read the contributing guide , README.md , code of conduct?

• Yes

[github-actions]

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[may-tas]

@GitMasterJatin LGTM, merging.