Fix: UnknownHashError in web.controllers.messages

[1yam]

If an hash is not valid it's would return a error 500 instead of returning Bad Request.

Related Clickup or Jira tickets : ALEPH-110

Self proofreading checklist

• Is my code clear enough and well documented
• Are my files well typed
• New translations have been added or updated if new strings have been introduced in the frontend
• Database migrations file are included
• Are there enough tests
• Documentation has been included (for new feature)

Changes

Add try catch on ItemHash().

How to test

http://localhost:4024/api/v0/messages/{wrong_itemhash}
http://localhost:4024/api/v0/messages/{wrong_itemhash}/content
http://localhost:4024/api/v0/messages/{wrong_itemhash}/status