Below are the steps necessary to hide an existing label from displaying throughout your project.
Within the 'Schema Editor', ensure "Labels" is highlighted in the 'Select' tab of the left sidebar.
Locate the label you'd like to hide and click anywhere within the label's displayed row, as shown below:
The view will update to display an edit form where you can change the 'Hidden' attribute of the existing label to "Yes" to hide that label from displaying throughout your project.
Click on the 'Save' button located on the toolbar to persist your changes to your project's database schema.