It seems that slash is the hard code.
As we are mainly responsible for general issue of Microsoft Teams, your question which is involved in development is not supported by us.
You can post a new thread in Teams developer forum where you will get the most qualified pool of respondents, and other partners who read the forums regularly can either share their knowledge or learn from your interaction.
Thank you for your understanding.
If the response is helpful, please click "Accept Answer" and upvote it.
Note: Please follow the steps in our documentation to enable e-mail notifications if you want to receive the related email notification for this thread.