fix: refactor replace_image_pullspec to use other helper functions #1216

Job	Run time
bash_unittests	9s
Run gitlint checks	5s
opa_policies_unittest	7s
Check Dockerfile	7s
Shellcheck	6s
YAML-Linter	4s
Call build and test workflow / Build and check main image	21m 10s
	21m 48s

Provide feedback