Fix typo

Author: alex268

auth-providers/oauth2-provider/src/main/java/tech/ydb/auth/OAuth2TokenExchangeProvider.java

@@ -276,7 +276,7 @@ private List<NameValuePair> fixedArgs() {
             List<NameValuePair> params = new ArrayList<>();
 
             // Required parameters
-            params.add(new BasicNameValuePair("grand_type", grantType));
+            params.add(new BasicNameValuePair("grant_type", grantType));
             params.add(new BasicNameValuePair("requested_token_type", requestedTokenType));
 
             // Optional parameters

auth-providers/oauth2-provider/src/test/java/tech/ydb/auth/OAuth2TokenExchangeProviderTest.java

@@ -104,7 +104,7 @@ private HttpResponse createResponse(String token, String tokenType, String scope
 
     private String requestForm(String token) {
         return Stream.of(
-                "grand_type=" + OAuth2TokenExchangeProvider.GRANT_TYPE,
+                "grant_type=" + OAuth2TokenExchangeProvider.GRANT_TYPE,
                 "requested_token_type=" + OAuth2TokenSource.ACCESS_TOKEN,
                 "subject_token=" + token,
                 "subject_token_type=" + OAuth2TokenSource.JWT_TOKEN
@@ -217,7 +217,7 @@ public void customRequestTest() {
             Assert.assertEquals("Bearer custom_token", identity.getToken());
 
             String form = Stream.of(
-                "grand_type=" + OAuth2TokenSource.ACCESS_TOKEN,
+                "grant_type=" + OAuth2TokenSource.ACCESS_TOKEN,
                 "requested_token_type=" + OAuth2TokenSource.REFRESH_TOKEN,
                 "resource=Resource",
                 "resource=OtherResource",