[ali_meeting] Fix some path errors for ali_meeting.py

[luomingshuang]

In the original ali_meeting.py, the line 99-103 is

            corpus_dir = (
                corpus_dir / f"{part}_Ali"
                if (corpus_dir / f"{part}_Ali").is_dir()
                else corpus_dir
            )

After the loop when the part is "Eval", the corpus_dir becomes corpus_dir / "Eval_Ali". And then, when comes to the loop that the part is "Test", the corpus_dir will be corpus_dir / "Eval_Ali" / "Test_Ali". However, corpus_dir / "Eval_Ali" / "Test_Ali" doesn't exist. It's wrong. So I change the codes from 99 to 105 line as follows:

        corpus_dir_split = corpus_dir
        if part == "Eval" or part == "Test":
            corpus_dir_split = (
                corpus_dir / f"{part}_Ali"
                if (corpus_dir / f"{part}_Ali").is_dir()
                else corpus_dir
            )
        wav_paths = corpus_dir_split / f"{part}_Ali_{mic}" / "audio_dir"
        text_paths = corpus_dir_split / f"{part}_Ali_{mic}" / "textgrid_dir"

If not do the above changes, there will be an error when generating the test manifest as follows (because the corpur_dir for test doesn't exist.):

[pzelasko]

Thanks!