fix: return AST import nodes from parseImports instead of strings

[Esorat]

Issue

Closes #965 .

Checklist

• I have updated CHANGELOG.md
• I have added tests to demonstrate the contribution is correctly implemented: this usually includes both positive and negative tests, showing the happy path(s) and featuring intentionally broken cases
• I have run all the tests locally and no test failure was reported
• I have run the linter, formatter and spellchecker
• I did not do unrelated and/or undiscussed refactorings

[anton-trunov]

Thanks for your contribution! You need to fix the type errors the linter warns you about (we have that "I have run the linter, formatter and spellchecker" checkbox for a reason).

Also, please add an entry to the changelog under the Changed section