Bump govuk_app_config from 9.2.0 to 9.4.0 #239

Job	Run time
Lint JavaScript / Run Standardx	16s
Lint Ruby / Run RuboCop	29s
Lint SCSS / Run Stylelint	17s
Test JavaScript / Run Jasmine	1m 3s
Test Ruby / Run RSpec	1m 49s
Security Analysis / Run Brakeman	22s
	4m 16s

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