docs: correct explanation on how to set custom signer via depinject (backport #23654)

[mergify]

Description

documentation was unclear, causing confusion for users. This should fix it.
cc @johnletey

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Summary by CodeRabbit

• New Features

  • Introduced enhanced transaction signing with support for custom message processing, improving how messages are structured and handled.

• Refactor

  • Streamlined the initialization and integration process for transaction signing to ensure a more robust and consistent configuration experience.

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This is an automatic backport of pull request #23654 done by [Mergify](https://mergify.com).

[mergify]

Cherry-pick of e3718e0 has failed:

On branch mergify/bp/release/v0.50.x/pr-23654
Your branch is up to date with 'origin/release/v0.50.x'.

You are currently cherry-picking commit e3718e06c.
  (fix conflicts and run "git cherry-pick --continue")
  (use "git cherry-pick --skip" to skip this patch)
  (use "git cherry-pick --abort" to cancel the cherry-pick operation)

Unmerged paths:
  (use "git add/rm <file>..." as appropriate to mark resolution)
	deleted by us:   docs/build/building-modules/02-messages-and-queries.md

no changes added to commit (use "git add" and/or "git commit -a")

To fix up this pull request, you can check it out locally. See documentation: https://docs.github.com/en/pull-requests/collaborating-with-pull-requests/reviewing-changes-in-pull-requests/checking-out-pull-requests-locally