[BUG][Java][resttemplate] Query param values not encoded anymore

Description

We are currently on OpenApi generator 5.4.0. Due to issues generating polymorphic classes we tried to upgrade to 6.0.1.

We are using a queryparam with a callback url of a string type currently.
In version 5.4.0 the ApiClient had this line:
if (value != null) { String templatizedKey = encodedName + valueItemCounter++; final String encodedValue = URLEncoder.encode(value.toString(), "UTF-8"); uriParams.put(templatizedKey, encodedValue); queryBuilder.append('=').append("{").append(templatizedKey).append("}"); }

In 6.0.1 the code changed to:
if (value != null) { String templatizedKey = encodedName + valueItemCounter++; uriParams.put(templatizedKey, value.toString()); queryBuilder.append('=').append("{").append(templatizedKey).append("}"); }

Without the encoding somehow our url changed from:
/some-mock/api/1.0/endpoint/method?callbackUrl=http:/**/**other-service/servicename/api/1.0/endpoint/method
to
/some-mock/api/1.0/endpoint/method?callbackUrl=http:/other-service/servicename/api/1.0/endpoint/method

This is a problem because i don't think http:/ would be a valid url. Also it breaks our wiremock expects in integration tests.

openapi-generator version

6.0.1.

Related issues/PRs

https://github.com/OpenAPITools/openapi-generator/issues/11921
https://github.com/OpenAPITools/openapi-generator/pull/11922

It seems mentioned PR and issue changed the behavior, but i am unsure as to how i should restore our application with this.

Start by comparing the Java RestTemplate ApiClient query-parameter handling in OpenAPI Generator 5.4.0 and 6.0.1, alongside issue 11921 and PR 11922. Restore the expected encoding behavior for callback URL query values and verify that generated URLs retain the encoded value used by the integration expectations.