ci/e2e-tests: streamline playwright tests

[alxndrsn]

Sibling PR to:

• ci/oidc-e2e: streamline playwright tests central-backend#1643
• ci: speed up playwright installs web-forms#532

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Ubuntu's man-db package updates can cause significant slowdown in job setup.

As there's no need for manpages in CI builds, the offending package can be removed.

See:

• man-db trigger severely stalls package installation on ubuntu-24.04 runners actions/runner#4030
• https://bugs.launchpad.net/ubuntu/+source/man-db/+bug/2073797
• ci/oidc-e2e: double job timeout central-backend#1642

What has been done to verify that this works as intended?

CI!

Why is this the best possible solution? Were any other approaches considered?

There are some other options discussed at https://stackoverflow.com/questions/76607092/google-compute-engine-processing-triggers-for-man-db-2-9-4-2-it-takes-a, but none are as simple, direct, and permanent as that used in this PR.

How does this change affect users? Describe intentional changes to behavior and behavior that could have accidentally been affected by code changes. In other words, what are the regression risks?

No effect - only affects CI.

Does this change require updates to user documentation? If so, please file an issue here and include the link below.

Nope.

Before submitting this PR, please make sure you have:

• run npm run test and npm run lint and confirmed all checks still pass OR confirm CircleCI build passes
• verified that any code or assets from external sources are properly credited in comments or that everything is internally sourced

[matthew-white]

@alxndrsn, how about if @brontolosone takes a look at this one, since he also reviewed getodk/central-backend#1643? I think @sadiqkhoja is most familiar with these e2e tests. I'm not super knowledgeable about them.