CCM-14318: Endpoints fetching letters return 500 instead of 404 when letter not found for supplier #3716

Job	Run time
Set CI/CD metadata	5s
Commit stage / Check Markdown format	7s
Commit stage / Scan secrets	12s
Commit stage / Detect Terraform Changes	5s
Commit stage / Count lines of code	7s
Commit stage / Check English usage	8s
Commit stage / Check TODO usage	4s
Commit stage / Scan dependencies	54s
Commit stage / Check file format	5s
Commit stage / Check for changes to event schema package compared to main branch	6s
Commit stage / Lint Terraform	0s
Commit stage / Run terraform-docs	0s
Commit stage / Check event schema version has been updated	-1s
Commit stage / Check for event schemas package version change	-1s
Test stage / Pact tests	1m 2s
Test stage / Check generated dependencies	50s
Test stage / Unit tests	3m 8s
Test stage / Linting	2m 52s
Test stage / Typecheck	1m 54s
Test stage / Test coverage	6s
Test stage / Perform static analysis	58s
Build stage / Create Dynamic Environment	6m 26s
Build stage / Build Docs	1m 32s
Build stage / Build OAS spec for sandbox	1m 2s
Build stage / Build SDKs	0s
Build stage / Build OAS spec (${{ matrix.apimEnv }})	0s
Acceptance stage / Run Acceptance Tests	4m 24s
Build stage / Build proxies	-1s
Acceptance stage / Run End-to-End Tests	-1s
Publish stage	0s
	26m 3s

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