Description

When you create a new template for a post that has no title, the "edit (title)" button in the toolbar
is printed, but it has no visible text:
<button type="button" data-toolbar-item="true" class="components-button edit-post-template-post-title is-link" aria-label="Edit "></button>

Step-by-step reproduction instructions

1. With template editing enabled, create a new post. Do not add a title to the post.
2. In the Template panel, select "new". Create a template.
3. When in the template editor, see that the template name and the arrow is visible,
   but there is no visible button above the template option modal that takes you back to the block editor.

Optionally, you can check that the markup for the button is printed, with the help of developer tools or view source.

Expected behaviour

I expect the button to be either completely removed, or have a text.

Actual behaviour

The button is printed but has no text. It is difficult to click on the button using the mouse, the click target area is too small.
But if you navigate via keyboard, you can select the button.

Screenshots or screen recording (optional)

Here you can see the label for the button and the focus style, when navigating via keyboard:

WordPress information

• WordPress version: 5.7.2. Not tested with 5.8 beta.
• Gutenberg version: Gutenberg current trunk
• Are all plugins except Gutenberg deactivated? yes
• Are you using a default theme (e.g. Twenty Twenty-One)? Twenty Nineteen

Device information

• Device: Desktop
• Operating system: Windows 10
• Browser: Chrome Version 91.0.4472.114