feat(dashscopeformatter): Support video block for dashscope

[qbc2016]

AgentScope Version

1.0.8

Description

1. Support video block for Dashscope
2. support promote audio and video from the tool result for Dashscope formatter

Checklist

Please check the following items before code is ready to be reviewed.

• [ ] Code has been formatted with pre-commit run --all-files command
• [ ] All tests are passing
• [ ] Docstrings are in Google style
• [ ] Related documentation has been updated (e.g. links, examples, etc.)
• [ ] Code is ready for review