clean up client HTTP 500 error message in general and also when task not found in database.

handling this frequent HTTP 500 ,when task not found, to HTTP 40X with more constructively, informatively messages. clean up flooded raw HTTP responses.

```
belforte@lxplus813/ste> crab status -d crab_20250226_192242/
Rucio client intialized for account belforte
Fatal error trying to connect to https://cmsweb-testbed.cern.ch:8443/crabserver/preprod/task?subresource=search&workflow=250226_182249%3Abelforte_crab_20250226_192242 using subresource=search&workflow=250226_182249%3Abelforte_crab_20250226_192242.
exit code from curl = 0
HTTP code/reason = 500/Internal Server Error . stdout:

500 Internal Server Error

#powered_by {
margin-top: 20px;
border-top: 2px solid black;
font-style: italic;
}

#traceback {
color: red;
}

500 Internal Server Error

Execution error

The server answered with an error.
Server answered with: Execution error
Reason is: Impossible to find task 250226_182249:belforte_crab_20250226_192242 in the database.
Error Id: 600683b4473ff85ea35000ea91786d7e
belforte@lxplus813/ste>