[2201.7.x] Update Host header only when the user intentionally provide a value

[TharmiganK]

Purpose

Related to: ballerina-platform/ballerina-library#6149

With this improvement we only overwrite the Host header when the user intentionally provide a value for that. Otherwise the Host header will be inferred from the client URL

Examples

final http:Client clientEP = check new("localhost:9091");

service /api on new http:Listener(9090) {

     resource function get test1(http:Request req) returns http:Response|error {
          // Here the `Host` header will be overwritten by the clientEP URL
          return clientEP->execute("get", "api/test", req);
     }

     resource function get test2(http:Request req) returns http:Response|error {
          // Header is intentionally overwritten by the user
          req.setHeader("Host", check req.getHeader("Host"));
          // The `Host` header will not be overwritten by the clientEP
          return clientEP->execute("get", "api/test", req);
     }
}

Checklist

• Linked to an issue
• Updated the changelog
• Added tests
• Updated the spec
• Checked native-image compatibility
• Checked the impact on OpenAPI generation

[sonarcloud]

Quality Gate passed

Issues
1 New issue
0 Accepted issues

Measures
0 Security Hotspots
No data about Coverage
0.0% Duplication on New Code

See analysis details on SonarCloud

[codecov]

Codecov Report

Attention: Patch coverage is 90.90909% with 1 lines in your changes are missing coverage. Please review.

Project coverage is 81.65%. Comparing base (b95f9d1) to head (972a7de).
Report is 1 commits behind head on 2201.7.x.

Files	Patch %	Lines
...lerina/stdlib/http/api/client/actions/Forward.java	50.00%	0 Missing and 1 partial ⚠️

Additional details and impacted files

@@              Coverage Diff               @@
##             2201.7.x    #1894      +/-   ##
==============================================
+ Coverage       81.55%   81.65%   +0.09%     
  Complexity        577      577              
==============================================
  Files             393      393              
  Lines           21409    21413       +4     
  Branches         4799     4800       +1     
==============================================
+ Hits            17461    17484      +23     
+ Misses           2951     2931      -20     
- Partials          997      998       +1     

☔ View full report in Codecov by Sentry.
📢 Have feedback on the report? Share it here.