Placeholder string is not translated in the Move subscription modal

Description of problem:

In the Move Subscription modal. the placeholder string in the search input field is not translated

Prerequisites (if any, like setup, operators/versions):

Steps to Reproduce

1. Create a Channel and a knative service
2. Add a subscription
3. click on the line joining the channel and the service (subscription)
4. click on actions dropdown -> Move subscription
5. Click on the sink dropdown 

Actual results:

The placeholder string is incorrect and is not translated

Expected results:

The placeholder string should be `Select a sink` 

Reproducibility (Always/Intermittent/Only Once):

Build Details:

4.9.0-0.nightly-2021-07-01-200539

Additional info: