fix: correctly adding contentType in java (#588)

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# Fixes #

Earlier contentType was set in java only when formParam or bodyParam was
present in the operation. However, the check should be about json-type
body or else. Corrected the mustache file.

### Checklist
- [x] I acknowledge that all my contributions will be made under the
project's license
- [ ] Run `make test-docker`
- [ ] Verify affected language:
- [ ] Generate [twilio-go](https://github.com/twilio/twilio-go) from our
[OpenAPI specification](https://github.com/twilio/twilio-oai) using the
[build_twilio_go.py](./examples/build_twilio_go.py) using `python
examples/build_twilio_go.py path/to/twilio-oai/spec/yaml
path/to/twilio-go` and inspect the diff
    - [ ] Run `make test` in `twilio-go`
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in the appropriate .md file
- [ ] I have added inline documentation to the code I modified

If you have questions, please create a GitHub Issue in this repository.

Author: tiwarishubham635

examples/java/src/main/java/com/twilio/rest/api/v2010/AccountDeleter.java

@@ -68,6 +68,7 @@ public boolean delete(final TwilioRestClient client) {
             Domains.API.toString(),
             path
         );
+        request.setContentType(EnumConstants.ContentType.FORM_URLENCODED);
         Response response = client.request(request);
 
         if (response == null) {

examples/java/src/main/java/com/twilio/rest/api/v2010/AccountFetcher.java

@@ -69,6 +69,7 @@ public Account fetch(final TwilioRestClient client) {
             Domains.API.toString(),
             path
         );
+        request.setContentType(EnumConstants.ContentType.FORM_URLENCODED);
         Response response = client.request(request);
 
         if (response == null) {

examples/java/src/main/java/com/twilio/rest/api/v2010/AccountReader.java

@@ -94,6 +94,7 @@ public Page<Account> firstPage(final TwilioRestClient client) {
         );
 
         addQueryParams(request);
+        request.setContentType(EnumConstants.ContentType.FORM_URLENCODED);
         return pageForRequest(client, request);
     }
 

examples/java/src/main/java/com/twilio/rest/api/v2010/account/CallDeleter.java

@@ -72,6 +72,7 @@ public boolean delete(final TwilioRestClient client) {
             Domains.API.toString(),
             path
         );
+        request.setContentType(EnumConstants.ContentType.FORM_URLENCODED);
         Response response = client.request(request);
 
         if (response == null) {

examples/java/src/main/java/com/twilio/rest/api/v2010/account/CallFetcher.java

@@ -73,6 +73,7 @@ public Call fetch(final TwilioRestClient client) {
             Domains.API.toString(),
             path
         );
+        request.setContentType(EnumConstants.ContentType.FORM_URLENCODED);
         Response response = client.request(request);
 
         if (response == null) {

examples/java/src/main/java/com/twilio/rest/flexapi/v1/CallUpdater.java

@@ -67,6 +67,7 @@ public Call update(final TwilioRestClient client){
             Domains.FLEXAPI.toString(),
             path
         );
+        request.setContentType(EnumConstants.ContentType.FORM_URLENCODED);
         Response response = client.request(request);
         if (response == null) {
             throw new ApiConnectionException("Call update failed: Unable to connect to server");

examples/java/src/main/java/com/twilio/rest/flexapi/v1/credential/AwsDeleter.java

@@ -65,6 +65,7 @@ public boolean delete(final TwilioRestClient client) {
             Domains.FLEXAPI.toString(),
             path
         );
+        request.setContentType(EnumConstants.ContentType.FORM_URLENCODED);
         Response response = client.request(request);
 
         if (response == null) {

examples/java/src/main/java/com/twilio/rest/flexapi/v1/credential/AwsFetcher.java

@@ -66,6 +66,7 @@ public Aws fetch(final TwilioRestClient client) {
             Domains.FLEXAPI.toString(),
             path
         );
+        request.setContentType(EnumConstants.ContentType.FORM_URLENCODED);
         Response response = client.request(request);
 
         if (response == null) {

examples/java/src/main/java/com/twilio/rest/flexapi/v1/credential/AwsReader.java

@@ -74,6 +74,7 @@ public Page<Aws> firstPage(final TwilioRestClient client) {
         );
 
         addQueryParams(request);
+        request.setContentType(EnumConstants.ContentType.FORM_URLENCODED);
         return pageForRequest(client, request);
     }
 

examples/java/src/main/java/com/twilio/rest/flexapi/v1/credential/aws/HistoryFetcher.java

@@ -72,6 +72,7 @@ public History fetch(final TwilioRestClient client) {
             path
         );
         addQueryParams(request);
+        request.setContentType(EnumConstants.ContentType.FORM_URLENCODED);
         Response response = client.request(request);
 
         if (response == null) {