fix errcheck issue (#28618)

Co-authored-by: Ben Schumacher <ben.schumacher@mattermost.com>

server/.golangci.yml

@@ -82,7 +82,6 @@ issues:
         channels/api4/post_test.go|\
         channels/api4/preference_test.go|\
         channels/api4/reaction_test.go|\
-        channels/api4/remote_cluster.go|\
         channels/api4/role.go|\
         channels/api4/saml.go|\
         channels/api4/scheme.go|\

server/channels/api4/remote_cluster.go

@@ -126,7 +126,9 @@ func remoteClusterAcceptMessage(c *Context, w http.ResponseWriter, r *http.Reque
 		return
 	}
 
-	w.Write(b)
+	if _, err := w.Write(b); err != nil {
+		c.Logger.Warn("Error while writing response", mlog.Err(err))
+	}
 }
 
 func remoteClusterConfirmInvite(c *Context, w http.ResponseWriter, r *http.Request) {
@@ -235,7 +237,11 @@ func uploadRemoteData(c *Context, w http.ResponseWriter, r *http.Request) {
 }
 
 func remoteSetProfileImage(c *Context, w http.ResponseWriter, r *http.Request) {
-	defer io.Copy(io.Discard, r.Body)
+	defer func() {
+		if _, err := io.Copy(io.Discard, r.Body); err != nil {
+			c.Logger.Warn("Error while reading request body", mlog.Err(err))
+		}
+	}()
 
 	c.RequireUserId()
 	if c.Err != nil {
@@ -344,7 +350,9 @@ func getRemoteClusters(c *Context, w http.ResponseWriter, r *http.Request) {
 		return
 	}
 
-	w.Write(b)
+	if _, err := w.Write(b); err != nil {
+		c.Logger.Warn("Error while writing response", mlog.Err(err))
+	}
 }
 
 func createRemoteCluster(c *Context, w http.ResponseWriter, r *http.Request) {
@@ -424,7 +432,9 @@ func createRemoteCluster(c *Context, w http.ResponseWriter, r *http.Request) {
 	}
 
 	w.WriteHeader(http.StatusCreated)
-	w.Write(b)
+	if _, err := w.Write(b); err != nil {
+		c.Logger.Warn("Error while writing response", mlog.Err(err))
+	}
 }
 
 func remoteClusterAcceptInvite(c *Context, w http.ResponseWriter, r *http.Request) {
@@ -491,7 +501,9 @@ func remoteClusterAcceptInvite(c *Context, w http.ResponseWriter, r *http.Reques
 	}
 
 	w.WriteHeader(http.StatusCreated)
-	w.Write(b)
+	if _, err := w.Write(b); err != nil {
+		c.Logger.Warn("Error while writing response", mlog.Err(err))
+	}
 }
 
 func generateRemoteClusterInvite(c *Context, w http.ResponseWriter, r *http.Request) {