Rewrite new_test.go removing duplications

[0xEbrahim]

Pull Request Template

related: #2436
issue: #2434

Description:

This PR refactors the HTTP service test suite to eliminate repetitive response validation logic and improve consistency across test cases.
It also fixes a mismatch between the expected and actual HTTP methods in one of the tests (previously PUT was expected instead of PATCH).

Breaking Changes (if applicable):

Added validateResponse Test Helper

• Declared in pkg/gofr/service/new_test.go
• Includes t.Helper() to mark it as a testing helper and satisfy the thelper linter rule.
• Handles response body closure safely (defer resp.Body.Close()).
• Performs unified assertions for success and error scenarios (require.NoError, assert.NotNil, etc.).
• Accepts hasError flag to differentiate between positive and negative test cases.

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Refactored All HTTP Method Tests

• Replaced duplicated response validation code with validateResponse calls.
• Unified structure across all GET, POST, PUT, PATCH, and DELETE test cases.
• Improved readability and consistency of test output and assertion style.

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Fixed HTTP Method Assertion

• A test previously asserted http.MethodPut while the service was using PATCH.
• The assertion has been corrected to match the intended HTTP method and avoid false test failures.

Additional Information:

• Mention any relevant dependencies or external libraries used.
• Include screenshots or code snippets (if necessary) to clarify the changes.

Checklist:

• I have formatted my code using goimport and golangci-lint.
• All new code is covered by unit tests.
• This PR does not decrease the overall code coverage.
• I have reviewed the code comments and documentation for clarity.

Thank you for your contribution!

[0xEbrahim]

@Umang01-hash please see this

[0xEbrahim]

@Umang01-hash I created a factory function to generate the service

[Umang01-hash]

@0xEbrahim The changes in all the other files apart from pkg/gofr/service/new_test.go are not necessary and also don't fall in the scope of this PR. Can you please remove them?

[0xEbrahim]

@Umang01-hash I think it is alright now, unless you have more comments