Add more linters to improve code readability (#19989)

Add nakedret, unconvert, wastedassign, stylecheck and nolintlint linters to improve code readability

- nakedret - https://github.com/alexkohler/nakedret - nakedret is a Go static analysis tool to find naked returns in functions greater than a specified function length.
- unconvert - https://github.com/mdempsky/unconvert - Remove unnecessary type conversions
- wastedassign - https://github.com/sanposhiho/wastedassign -  wastedassign finds wasted assignment statements.
- notlintlint -  Reports ill-formed or insufficient nolint directives
- stylecheck - https://staticcheck.io/docs/checks/#ST - keep style consistent
  - excluded: [ST1003 - Poorly chosen identifier](https://staticcheck.io/docs/checks/#ST1003) and [ST1005 - Incorrectly formatted error string](https://staticcheck.io/docs/checks/#ST1005)

integrations/oauth_test.go

@@ -197,7 +197,7 @@ func TestAccessTokenExchangeWithBasicAuth(t *testing.T) {
 		"code_verifier": "N1Zo9-8Rfwhkt68r1r29ty8YwIraXR8eh_1Qwxg7yQXsonBt", // test PKCE additionally
 	})
 	req.Header.Add("Authorization", "Basic ZGE3ZGEzYmEtOWExMy00MTY3LTg1NmYtMzg5OWRlMGIwMTM4OmJsYWJsYQ==")
-	resp = MakeRequest(t, req, http.StatusBadRequest)
+	MakeRequest(t, req, http.StatusBadRequest)
 
 	// missing header
 	req = NewRequestWithValues(t, "POST", "/login/oauth/access_token", map[string]string{
@@ -206,7 +206,7 @@ func TestAccessTokenExchangeWithBasicAuth(t *testing.T) {
 		"code":          "authcode",
 		"code_verifier": "N1Zo9-8Rfwhkt68r1r29ty8YwIraXR8eh_1Qwxg7yQXsonBt", // test PKCE additionally
 	})
-	resp = MakeRequest(t, req, http.StatusBadRequest)
+	MakeRequest(t, req, http.StatusBadRequest)
 }
 
 func TestRefreshTokenInvalidation(t *testing.T) {