docs(screenshots): add step for specific component testing (#29594)

Issue number: N/A

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## What is the current behavior?
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There is no documentation on how to use the input field in the
screenshots GH actions.

## What is the new behavior?
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this PR. -->

- Added steps and examples on how to specify a component within
screenshots GH actions.

## Does this introduce a breaking change?

- [ ] Yes
- [x] No

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## Other information

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screenshots of how the component looks before and after the change. -->

N/A