Unable to create secret while starting pipelinerun

1.9.x

Always

1. Create a pipeline
2. Click on Start option from dropdown menu
3. In *Advanced options* section click on *Show credentials options*
4. Click on *Add Secret* button 
5. Provide name for the secret
6. In *Access to* dropdown select *Git Server*
7. In *Authentication type* dropdown select *SSH Key*
8. Provide *github.com* as value for *Server URL*
9. Click on *Browse* button and select the ssh key
10. Click on tick mark

Adding ssh secret is getting failed with the error below error.
*Error "Required value" for field "data[ssh-privatekey]".*

The secret should get created