Header with bold and a link in dark mode have a white shadow.

[SergioEstevao]

Describe the bug

If you have a header block with a link and with strong applied to the text you will see a white shadow:

To reproduce
Steps to reproduce the behavior:
Make sure the device is running in dark mode.

1. Open the demo app
2. Add a header block
3. Write some text
4. Apply a link to a part of the text
5. Apply the Strong attributed to the link
6. See the error

Expected behavior

You shouldn't see a white shadow around the link text.

Screenshots

Editor version (please complete the following information):

• WordPress version: Any
• Does the website have the Gutenberg plugin installed, or is it using the block editor that comes by default? [e.g: "gutenberg plugin", "default"]
• If the Gutenberg plugin is installed, which version is it? [e.g., 7.6]

Smartphone (please complete the following information):

• Device: iPhone
• OS: iOS 13
• WordPress App Version: 15.3 or Demo App Version 1.33.0

Additional context

• To report a security issue, please visit the WordPress HackerOne program: https://hackerone.com/wordpress.