Log httpx errors with repr (#1188)

Some httpx errors have empty descriptions, e.g.
`ReadError("")`, so logging with `str` is not
informative. Logging with `repr` will allow to see
the exception type.

gateway/src/dstack/gateway/core/auth.py

@@ -24,7 +24,7 @@ async def has_access(self, project: str, token: str) -> bool:
             if resp.status_code == 200:
                 return True
         except httpx.RequestError as e:
-            logger.debug("Failed to check access: %s", e)
+            logger.debug("Failed to check access: %r", e)
         return False
 
 

src/dstack/_internal/server/services/gateways/__init__.py

@@ -365,7 +365,7 @@ async def register_service(session: AsyncSession, run_model: RunModel):
     except SSHError:
         raise ServerClientError("Gateway tunnel is not working")
     except httpx.RequestError as e:
-        raise GatewayError(f"Gateway is not working: {e}")
+        raise GatewayError(f"Gateway is not working: {e!r}")
 
 
 async def register_replica(
@@ -382,7 +382,7 @@ async def register_replica(
             )
         logger.info("%s: replica is registered for service %s", fmt(job_model), run.id.hex)
     except (httpx.RequestError, SSHError) as e:
-        raise GatewayError(str(e))
+        raise GatewayError(repr(e))
 
 
 async def unregister_service(session: AsyncSession, run_model: RunModel):
@@ -400,7 +400,7 @@ async def unregister_service(session: AsyncSession, run_model: RunModel):
         # ignore if service is not registered
         logger.warning("%s: unregistering service: %s", fmt(run_model), e)
     except (httpx.RequestError, SSHError) as e:
-        raise GatewayError(str(e))
+        raise GatewayError(repr(e))
 
 
 async def unregister_replica(session: AsyncSession, job_model: JobModel):
@@ -431,7 +431,7 @@ async def unregister_replica(session: AsyncSession, job_model: JobModel):
         # ignore if replica is not registered
         logger.warning("%s: unregistering replica from service: %s", fmt(job_model), e)
     except (httpx.RequestError, SSHError) as e:
-        raise GatewayError(str(e))
+        raise GatewayError(repr(e))
 
 
 async def get_gateway_connection(