MM-52532: Fix golangci warnings for public module (#23918)

https://mattermost.atlassian.net/browse/MM-52532

```release-note
NONE
```

server/public/model/post.go

@@ -207,11 +207,11 @@ type AnalyticsPostCountsOptions struct {
 }
 
 func (o *PostPatch) WithRewrittenImageURLs(f func(string) string) *PostPatch {
-	copy := *o //nolint:revive
-	if copy.Message != nil {
-		*copy.Message = RewriteImageURLs(*o.Message, f)
+	pCopy := *o //nolint:revive
+	if pCopy.Message != nil {
+		*pCopy.Message = RewriteImageURLs(*o.Message, f)
 	}
-	return &copy
+	return &pCopy
 }
 
 func (o *PostPatch) Auditable() map[string]interface{} {
@@ -296,15 +296,15 @@ func (o *Post) ShallowCopy(dst *Post) error {
 
 // Clone shallowly copies the post and returns the copy.
 func (o *Post) Clone() *Post {
-	copy := &Post{} //nolint:revive
-	o.ShallowCopy(copy)
-	return copy
+	pCopy := &Post{} //nolint:revive
+	o.ShallowCopy(pCopy)
+	return pCopy
 }
 
 func (o *Post) ToJSON() (string, error) {
-	copy := o.Clone() //nolint:revive
-	copy.StripActionIntegrations()
-	b, err := json.Marshal(copy)
+	pCopy := o.Clone() //nolint:revive
+	pCopy.StripActionIntegrations()
+	b, err := json.Marshal(pCopy)
 	return string(b), err
 }
 
@@ -707,12 +707,12 @@ var markdownDestinationEscaper = strings.NewReplacer(
 // WithRewrittenImageURLs returns a new shallow copy of the post where the message has been
 // rewritten via RewriteImageURLs.
 func (o *Post) WithRewrittenImageURLs(f func(string) string) *Post {
-	copy := o.Clone()
-	copy.Message = RewriteImageURLs(o.Message, f)
-	if copy.MessageSource == "" && copy.Message != o.Message {
-		copy.MessageSource = o.Message
+	pCopy := o.Clone()
+	pCopy.Message = RewriteImageURLs(o.Message, f)
+	if pCopy.MessageSource == "" && pCopy.Message != o.Message {
+		pCopy.MessageSource = o.Message
 	}
-	return copy
+	return pCopy
 }
 
 // RewriteImageURLs takes a message and returns a copy that has all of the image URLs replaced