User Feedback Widget: Defining theme requires all properties to be filled out

[bruno-garcia]

Code snippets instructing how to tweak the theme:

sentry-javascript/packages/feedback/README.md

Lines 126 to 128 in b2a56bc

	themeLight: {
	background: "#cccccc",
	},

Results in a TS error:

Ideally all properties would be optional. And whatever was set gets merged with the default values.

[bruno-garcia]

On alpha.7 this seems resolved. But on 0.0.1-alpha.8 I still struggle with this.

[billyvg]

I may have pushed a bad .8 build, but .9 is working.