transform-imports: side-effect imports are not being transformed

[jsbravoc]

Describe the bug
Side effect imports are not being transformed. The plugin currently ignores these imports when they should be transformed. See original issue #329, the expected output is to have both imports transformed.

URL to minimal reproduction
The tests assert this behavior: https://github.com/swc-project/plugins/tree/main/packages/transform-imports/transform/tests/fixture/side-effect-imports

Expected behavior
Side-effect imports should be transformed

• Input

import './upload/upload.ts';

• Output

import './upload/upload.js';

Additional context

Proposed a solution here: #473