New review approvals shouldn't require a message (#8991)

* New approvals don't require content

Signed-off-by: jolheiser <john.olheiser@gmail.com>

* Fix edge-bug

Signed-off-by: jolheiser <john.olheiser@gmail.com>

models/review.go

@@ -254,7 +254,7 @@ func SubmitReview(doer *User, issue *Issue, reviewType ReviewType, content strin
 			return nil, nil, err
 		}
 
-		if len(strings.TrimSpace(content)) == 0 {
+		if reviewType != ReviewTypeApprove && len(strings.TrimSpace(content)) == 0 {
 			return nil, nil, ContentEmptyErr{}
 		}
 
@@ -272,7 +272,7 @@ func SubmitReview(doer *User, issue *Issue, reviewType ReviewType, content strin
 		if err := review.loadCodeComments(sess); err != nil {
 			return nil, nil, err
 		}
-		if len(review.CodeComments) == 0 && len(strings.TrimSpace(content)) == 0 {
+		if reviewType != ReviewTypeApprove && len(review.CodeComments) == 0 && len(strings.TrimSpace(content)) == 0 {
 			return nil, nil, ContentEmptyErr{}
 		}