fix(services/dropbox): fix dropbox ci

[zjregee]

fix: #4484

There are several issues that need to be fixed here, related ci: https://github.com/apache/opendal/actions/runs/8682043318/job/23805843756.

Error caused by Dropbox service not supporting:

• test_copy_overwrite
• test_copy_file_with_non_ascii_name
• test_rename_overwrite
• test_list_prefix
• test_list_file_with_recursive

Should return an error when it does not exist:

• test_copy_non_existing_source
• test_rename_non_existing_source

Returned by list does not contact the complete path:

• test_list_dir
• test_list_dir_with_metakey
• test_list_dir_with_metakey_complete
• test_list_rich_dir
• test_list_nested_dir
• test_list_dir_with_recursive
• test_list_dir_with_recursive_no_trailing_slash

List dir should only return dir/

• test_list_empty_dir
• test_list_dir_with_file_path

[tisonkun]

Is this still relevant? It seems no dropbox CI failures recently.

[Xuanwo]

Is this still relevant? It seems no dropbox CI failures recently.

dropbox CI has been disabled.

[Xuanwo]

Hi @zjregee, thank you for working on this. I'm going to close this PR to clean up the stale state. If you're still interested in fixing it, I'm happy to help enable the dropbox tests and work with you to get it merged.