Support for request content mutation.

[vbothe23]

Description of what I changed

Fixes issue: #258

• Added an attribute requestContent in the RequestMutation class.
• In mutateRequest() function, added check for the request content.
  • If the request content is modified by the plugin, then replacing the actual content with modified content.

E2E test

TESTED:

Please replace this with a description of how you tested your PR beyond the automated e2e/unit tests.

Checklist: I completed these to help reviewers :)

• [x] I have read and will follow the review process.

• [ ] I am familiar with Google Style Guides for the language I have coded in.

  No? Please take some time and review Java and Python style guides.

• [ ] My IDE is configured to follow the Google code styles.

  No? Unsure? -> configure your IDE.

• [ ] I have added tests to cover my changes. (If you refactored existing code that was well tested you do not have to add tests)

• [x] I ran mvn clean package right before creating this pull request and added all formatting changes to my commit.

• [ ] All new and existing tests passed.

• [ ] My pull request is based on the latest changes of the master branch.

  No? Unsure? -> execute command git pull --rebase upstream master

[vbothe23]

Hi @bashir2 , As per our discussion, I have raised this draft PR. Please review the changes that I have implemented.

[codecov-commenter]

Codecov Report

Attention: Patch coverage is 62.50000% with 3 lines in your changes are missing coverage. Please review.

Project coverage is 69.78%. Comparing base (f0788a6) to head (75d0265).

Files	Patch %	Lines
...e/fhir/gateway/BearerAuthorizationInterceptor.java	57.14%	1 Missing and 2 partials :warning:

Additional details and impacted files

```diff @@ Coverage Diff @@ ## main #265 +/- ## ============================================ - Coverage 69.84% 69.78% -0.06% - Complexity 342 343 +1 ============================================ Files 26 26 Lines 1343 1347 +4 Branches 212 214 +2 ============================================ + Hits 938 940 +2 - Misses 318 319 +1 - Partials 87 88 +1 ```

:umbrella: View full report in Codecov by Sentry.
:loudspeaker: Have feedback on the report? Share it here.

[vbothe23]

Thanks @bashir2, for sharing the concerns about the request mutation. As discussed, we decided to proceed with the prostProcess approach, which mutate the response from the FHIR server, rather than the request data goes into the server. Thus our problem will be solved without these code changes.