Remove coverage offsets related code

[rohitvinnakota-codecov]

Purpose/Motivation

What is the feature? Why is this being done?

Following up from https://github.com/codecov/codecov-api/pull/780, remove unused code pertaining to the old YAML field. This closes https://github.com/orgs/codecov/projects/31/views/11?pane=issue&itemId=77144226.

Links to relevant tickets

Legal Boilerplate

Look, I get it. The entity doing business as "Sentry" was incorporated in the State of Delaware in 2015 as Functional Software, Inc. In 2022 this entity acquired Codecov and as result Sentry is going to need some rights from me in order to utilize my contributions in this PR. So here's the deal: I retain all rights, title and interest in and to my contributions, and by keeping this boilerplate intact I confirm that Sentry can use, modify, copy, and redistribute my contributions, under Sentry's choice of terms.

[rohitvinnakota-codecov]

@codecov-ai-reviewer

[codecov-notifications[bot]]

Codecov Report

All modified and coverable lines are covered by tests :white_check_mark:

:white_check_mark: All tests successful. No failed tests found.

:loudspeaker: Thoughts on this report? Let us know!

[codecov[bot]]

Codecov Report

All modified and coverable lines are covered by tests :white_check_mark:

Project coverage is 96.23%. Comparing base (ad7e3af) to head (04eccda). Report is 1 commits behind head on main.

:white_check_mark: All tests successful. No failed tests found.

Additional details and impacted files

```diff @@ Coverage Diff @@ ## main #822 +/- ## =========================================== Coverage 96.23000 96.23000 =========================================== Files 812 812 Lines 18552 18549 -3 =========================================== - Hits 17853 17850 -3 Misses 699 699 ``` | [Flag](https://app.codecov.io/gh/codecov/codecov-api/pull/822/flags?src=pr&el=flags&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=codecov) | Coverage Δ | | |---|---|---| | [unit](https://app.codecov.io/gh/codecov/codecov-api/pull/822/flags?src=pr&el=flag&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=codecov) | `92.45% <ø> (-0.01%)` | :arrow_down: | | [unit-latest-uploader](https://app.codecov.io/gh/codecov/codecov-api/pull/822/flags?src=pr&el=flag&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=codecov) | `92.45% <ø> (-0.01%)` | :arrow_down: | Flags with carried forward coverage won't be shown. [Click here](https://docs.codecov.io/docs/carryforward-flags?utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=codecov#carryforward-flags-in-the-pull-request-comment) to find out more.

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