Reland "Include host and project in code-owners not enabled error."

This is a reland of commit 4d2728b03e2c567c95dac8899855dc9b0f706b86

Added default values for host and project in case input.gerrit does not
exist.

Original change's description:
> Include host and project in code-owners not enabled error.
>
> Bug: 329231688
> Change-Id: I36bb24f167854f40718ec49559d9aaa640fa1a44
> Reviewed-on: https://chromium-review.googlesource.com/c/chromium/tools/depot_tools/+/5384365
> Auto-Submit: Joanna Wang <jojwang@chromium.org>
> Commit-Queue: Joanna Wang <jojwang@chromium.org>
> Reviewed-by: Scott Lee <ddoman@chromium.org>
> Commit-Queue: Scott Lee <ddoman@chromium.org>

Bug: 329231688
Change-Id: If65e362d0aba97d804a75c078452bab8152ae224
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/tools/depot_tools/+/5384366
Auto-Submit: Joanna Wang <jojwang@chromium.org>
Reviewed-by: Scott Lee <ddoman@chromium.org>
Commit-Queue: Joanna Wang <jojwang@chromium.org>
Commit-Queue: Scott Lee <ddoman@chromium.org>

presubmit_canned_checks.py

@@ -1548,9 +1548,15 @@ def CheckOwnersFormat(input_api, output_api):
     if input_api.gerrit and input_api.gerrit.IsCodeOwnersEnabledOnRepo():
         return []
 
+    host = "none"
+    project = "none"
+    if input_api.gerrit:
+        host = input_api.gerrit.host
+        project = input_api.gerrit.project
     return [
         output_api.PresubmitError(
-            'code-owners is not enabled. Ask your host enable it on your gerrit '
+            f'code-owners is not enabled on {host}/{project}. '
+            'Ask your host enable it on your gerrit '
             'host. Read more about code-owners at '
             'https://chromium-review.googlesource.com/'
             'plugins/code-owners/Documentation/index.html.')
@@ -1568,9 +1574,15 @@ def CheckOwners(input_api, output_api, source_file_filter=None, allow_tbr=True):
     if input_api.gerrit and input_api.gerrit.IsCodeOwnersEnabledOnRepo():
         return []
 
+    host = "none"
+    project = "none"
+    if input_api.gerrit:
+        host = input_api.gerrit.host
+        project = input_api.gerrit.project
     return [
         output_api.PresubmitError(
-            'code-owners is not enabled. Ask your host enable it on your gerrit '
+            f'code-owners is not enabled on {host}/{project}. '
+            'Ask your host enable it on your gerrit '
             'host. Read more about code-owners at '
             'https://chromium-review.googlesource.com/'
             'plugins/code-owners/Documentation/index.html.')