fix: the bug in dataset get request

Type of change

• Bug Fix
• Feature
• Pipeline
• Test

Does this introduce a change in the core logic?

• No
• Yes

Does this introduce a change in the cloud provider implementation, if so which cloud?

• AWS
• Azure
• GCP
• IBM

Does this follow conventional commits spec?

• No
• Yes

Have you set the target Milestone?

• No
• Yes

Have you set the no-detached-pipeline label?

• No
• Yes

Updates description?

When trying to retrieve dataset which doesn't exist with the user who is not authorized to make this request, the clinet would receive 404 instead of 403 (fordidden). With this modifications when dataset doesn't exist we recheck if user even had a permission to make this type of request and return 403 instead of 404 if it didn't.