Restore link to help docs in DCA

[aclayton555]

Currently, there is no link to the data ingress docs from the DCA interface.

Checked with Amy H about this, looks like we need to add to the DCA config in GitHub (there is a spot to add it, not sure if it was never added or somehow removed??) ->> https://github.com/Sage-Bionetworks/data_curator_config/blob/prod/HTAN/dca_config.json

See "..._help_link"

Could link to: https://dca-docs.scrollhelp.site/DCA/Working-version/HTAN/welcome

If we want, we could also link to https://docs.humantumoratlas.org/

[adamjtaylor]

Completed in Sage-Bionetworks/data_curator_config#189

Now deployed