Update section-running-jobs-in-a-container.md

[richseviora]

Adds a note and example explaining that the working directory may need to be set when using a custom container.

Why:

Closes: #37027

What's being changed (if available, include any code snippets, screenshots, or gifs):

I'm adding a section to the Run jobs in a container article to warn users that they may need to set the working-directory option if they are supply a custom image. I also provide an example of the configuration file.

Check off the following:

• A subject matter expert (SME) has reviewed the technical accuracy of the content in this PR. In most cases, the author can be the SME. Open source contributions may require an SME review from GitHub staff.
• The changes in this PR meet the docs fundamentals that are required for all content.
• All CI checks are passing and the changes look good in the review environment.

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Source	Review	Production	What Changed
actions/writing-workflows/choosing-where-your-workflow-runs/running-jobs-in-a-container.md	fpt ghec ghes@ 3.16 3.15 3.14 3.13 3.12	fpt ghec ghes@ 3.16 3.15 3.14 3.13 3.12	from reusable
actions/writing-workflows/workflow-syntax-for-github-actions.md	fpt ghec ghes@ 3.16 3.15 3.14 3.13 3.12	fpt ghec ghes@ 3.16 3.15 3.14 3.13 3.12	from reusable

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[Sharra-writes]

Waiting on SME review here.