Some block patterns have text contrast issues with dark themes

[nrqsnchz]

Moving from ​https://github.com/WordPress/gutenberg/issues/24391

Some block patterns are presenting text contrast issues on dark themes. The patterns with the issue are:

• Two columns of text
• Two columns of text with images
• Three columns of text with buttons
• Heading and Paragraph

These patterns have the text color of body copy hardcoded to black, which causes the aforementioned issues when viewed on a dark theme.

[nrqsnchz]

I've uploaded a patch with a fix. It removes the hardcoded value only from body text. Patterns should now respect the theme's default text color.

I also tested on Core default themes (from Twenty Ten to Twenty Twenty) and couldn't see any issues there due to this change.

[SergeyBiryukov]

In 48864:

Editor: Remove some hardcoded text color values from patterns that have body text with no specific background color.

This ensures that the patterns respect the theme's default color for body text and avoids contrast issues, particularly in dark themes.

Props nrqsnchz, mapk, fullofcaffeine.
Fixes #50892.

[SergeyBiryukov]

In 48865:

Editor: Remove some hardcoded text color values from patterns that have body text with no specific background color.

This ensures that the patterns respect the theme's default color for body text and avoids contrast issues, particularly in dark themes.

Props nrqsnchz, mapk, fullofcaffeine.
Merges [48864] to the 5.5 branch.
Fixes #50892.