fix(ci): use a bigger machine for config file tests

[gustavovalverde]

Motivation

We've been having this issue from time to time, but as there's nothing in the Zebra config or on the Rust side that could cause this issue, and all the other similar tests are passing, the most probable cause is we're using more memory than the default runners from GitHub are giving us when using this configuration.

Note: Removing the exec command should be our last resort if this does not work by any means.

Closes: #7898

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Solution

• Use a bigger runner with more memory. In this case ubuntu-latest-m

Testing

Run this test at least 5 times. It should be really fast to do.

Review

Nothing specific.

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[teor2345]

Let's also merge this failure fix