Bump govuk_publishing_components from 35.14.0 to 35.15.0 #442

Job	Run time
Lint SCSS / Run Stylelint	22s
Lint JavaScript / Run Standardx	16s
Security Analysis / Run Brakeman	22s
Lint Ruby / Run RuboCop	38s
Test JavaScript / Run Jasmine	1m 16s
Test Ruby / Run RSpec	3m 40s
	6m 34s

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