Make sure if the textColor is changed the default text color is updated.

[SergioEstevao]

This change make sure that if the textColor prop is set explicitly we also update the defaultTextColor is used in TextView

To test:

• Try to change the prop style on RichText uses to something like: style={ { color: 'red' }}
• See if the color is applied.

Update release notes:

• If there are user facing changes, I have added an item to RELEASE-NOTES.txt.

[pinarol]

This is fixing the regression we are having 👍 I can see that the captions are white again.