chore(build): Remove misplaced fetch-depth option in ember CI build

[lobsterkatie]

In #3610, a change was made to the ember tests in CI, to fix an unspecified problem with checking out the relevant commit for testing. Unfortunately, the change was added in the wrong spot. As a result,

1. the problem wasn't fixed, and
2. we started getting warnings in CI like this:

Problem 1 was fixed in 9b5ab61#diff-5c3fa597431eda03ac3339ae6bf7f05e1a50d6fc7333679ec38e21b337cb6721, by adding the option to the right spot (again, for an unspecified reason).

This PR fixes problem 2, by removing the option from the wrong spot.

Given the mystery surrounding the addition of fetch-depth in the first place, it also adds a TODO to reconsider if we need it once ember tests are again all passing.

[github-actions]

This pull request has gone three weeks without activity. In another week, I will close it.

But! If you comment or otherwise update it, I will reset the clock, and if you label it Status: Backlog or Status: In Progress, I will leave it alone ... forever!

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"A weed is but an unloved flower." ― Ella Wheeler Wilcox 🥀

[github-actions]

size-limit report

Path	Base Size (e5ede4c)	Current Size	Change
@sentry/browser - CDN Bundle (gzipped)	19.73 KB	19.77 KB	+0.2% 🔺
@sentry/browser - CDN Bundle (minified)	62.78 KB	62.94 KB	+0.27% 🔺
@sentry/browser - Webpack	22.26 KB	22.31 KB	+0.22% 🔺
@sentry/browser - Webpack - gzip = false	75.93 KB	76.19 KB	+0.34% 🔺
@sentry/react - Webpack	22.29 KB	22.34 KB	+0.22% 🔺
@sentry/nextjs Client - Webpack	46.42 KB	46.48 KB	+0.14% 🔺
@sentry/browser + @sentry/tracing - CDN Bundle (gzipped)	28.39 KB	28.43 KB	+0.16% 🔺