RUM-4374: Emulate upload network call for functional tests

[0xnm]

What does this PR do?

Right now we are calling the real intake for the functional tests of Gradle Plugin, and since we don’t have a real API key, we get an error and we expect build failure in our tests. However, it may be some other build failures, so it is handy to emulate network call to make test expectation without any build failures.

This PR adds build parameter dd-emulate-upload-call which can be passed for the build script execution. If it is present, no real network call will be made and we will create a fake response.

Review checklist (to be filled by reviewers)

• [ ] Feature or bugfix MUST have appropriate tests (unit, integration, e2e)
• [ ] Make sure you discussed the feature or bugfix with the maintaining team in an Issue
• [ ] Make sure each commit and the PR mention the Issue number (cf the CONTRIBUTING doc)

[codecov-commenter]

Codecov Report

Attention: Patch coverage is 33.33333% with 10 lines in your changes are missing coverage. Please review.

Project coverage is 80.78%. Comparing base (b1ee483) to head (c3626c4).

Additional details and impacted files

```diff @@ Coverage Diff @@ ## develop #255 +/- ## ============================================= - Coverage 81.48% 80.78% -0.70% - Complexity 203 205 +2 ============================================= Files 26 26 Lines 810 822 +12 Branches 104 105 +1 ============================================= + Hits 660 664 +4 - Misses 112 121 +9 + Partials 38 37 -1 ``` | [Files](https://app.codecov.io/gh/DataDog/dd-sdk-android-gradle-plugin/pull/255?dropdown=coverage&src=pr&el=tree&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=DataDog) | Coverage Δ | | |---|---|---| | [...tlin/com/datadog/gradle/plugin/DdFileUploadTask.kt](https://app.codecov.io/gh/DataDog/dd-sdk-android-gradle-plugin/pull/255?src=pr&el=tree&filepath=dd-sdk-android-gradle-plugin%2Fsrc%2Fmain%2Fkotlin%2Fcom%2Fdatadog%2Fgradle%2Fplugin%2FDdFileUploadTask.kt&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=DataDog#diff-ZGQtc2RrLWFuZHJvaWQtZ3JhZGxlLXBsdWdpbi9zcmMvbWFpbi9rb3RsaW4vY29tL2RhdGFkb2cvZ3JhZGxlL3BsdWdpbi9EZEZpbGVVcGxvYWRUYXNrLmt0) | `82.54% <80.00%> (+1.09%)` | :arrow_up: | | [...lin/com/datadog/gradle/plugin/internal/Uploader.kt](https://app.codecov.io/gh/DataDog/dd-sdk-android-gradle-plugin/pull/255?src=pr&el=tree&filepath=dd-sdk-android-gradle-plugin%2Fsrc%2Fmain%2Fkotlin%2Fcom%2Fdatadog%2Fgradle%2Fplugin%2Finternal%2FUploader.kt&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=DataDog#diff-ZGQtc2RrLWFuZHJvaWQtZ3JhZGxlLXBsdWdpbi9zcmMvbWFpbi9rb3RsaW4vY29tL2RhdGFkb2cvZ3JhZGxlL3BsdWdpbi9pbnRlcm5hbC9VcGxvYWRlci5rdA==) | `72.73% <0.00%> (-27.27%)` | :arrow_down: | | [...m/datadog/gradle/plugin/internal/OkHttpUploader.kt](https://app.codecov.io/gh/DataDog/dd-sdk-android-gradle-plugin/pull/255?src=pr&el=tree&filepath=dd-sdk-android-gradle-plugin%2Fsrc%2Fmain%2Fkotlin%2Fcom%2Fdatadog%2Fgradle%2Fplugin%2Finternal%2FOkHttpUploader.kt&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=DataDog#diff-ZGQtc2RrLWFuZHJvaWQtZ3JhZGxlLXBsdWdpbi9zcmMvbWFpbi9rb3RsaW4vY29tL2RhdGFkb2cvZ3JhZGxlL3BsdWdpbi9pbnRlcm5hbC9Pa0h0dHBVcGxvYWRlci5rdA==) | `78.20% <12.50%> (-4.34%)` | :arrow_down: | ... and [1 file with indirect coverage changes](https://app.codecov.io/gh/DataDog/dd-sdk-android-gradle-plugin/pull/255/indirect-changes?src=pr&el=tree-more&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=DataDog)