fix: don't display pending reviews as participants (#10528)

Fixes #10155

When participants are displayed, don't include those that only have made a pending review. Those should not yet be revealed as participants.

Apart from adding automated tests, this is the manual verification process I've followed:
1. Set up three users
2. User 1 creates a repository, then creates a pull request adding a new file
3. User 2 creates a new code comment but doesn't not publish the review, shows as pending.
4. User 3 creates a new code comment and publishes the review.
5. From everyone's perspective the number of participants is: 2. And, the participants displayed in the list are 1 and 3. User 2, which hasn't yet published the review is not displayed.

Reviewed-on: https://codeberg.org/forgejo/forgejo/pulls/10528
Reviewed-by: Gusted <gusted@noreply.codeberg.org>
Co-authored-by: luisadame <luisadame@noreply.codeberg.org>
Co-committed-by: luisadame <luisadame@noreply.codeberg.org>

services/mailer/fixtures/TestCloseIssue/comment.yml

@@ -0,0 +1,10 @@
+- id: 1001
+  type: 21 # code comment
+  poster_id: 10
+  issue_id: 1
+  review_id: 1001
+  content: "Some code comment that is pending to be published"
+  line: -4
+  tree_path: "README.md"
+  created_unix: 946684812
+  invalidated: false

services/mailer/fixtures/TestCloseIssue/review.yml

@@ -0,0 +1,7 @@
+- id: 1001
+  type: 0 # Pending review
+  reviewer_id: 10
+  issue_id: 1
+  content: "Pending review for issue 1"
+  updated_unix: 946684810
+  created_unix: 946684810

services/mailer/mail_issue_test.go

@@ -18,6 +18,7 @@ import (
 )
 
 func TestCloseIssue(t *testing.T) {
+	defer unittest.OverrideFixtures("services/mailer/fixtures/TestCloseIssue")()
 	defer require.NoError(t, unittest.PrepareTestDatabase())
 
 	called := false