[8.19](backport #7919) [Asset Inventory][EC2] Add timeout handler to IAM resolver

[mergify]

Summary of your changes

Add 10s timeout to GetInstanceProfile calls in EC2 instance fetcher

The IAM client uses the default HTTP transport with no timeout. If GetInstanceProfile hangs, the fetch loop blocks before sending any asset to the channel, so zero EC2 assets are published. Errors are already handled gracefully (falls back to the profile ARN), so a timeout is enough to resolve any issues.

Related Issues

Resolves error for integration tests.

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This is an automatic backport of pull request #7919 done by [Mergify](https://mergify.com).

[mergify]

Cherry-pick of e1ea204 has failed:

On branch mergify/bp/8.19/pr-7919
Your branch is up to date with 'origin/8.19'.

You are currently cherry-picking commit e1ea204a.
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Unmerged paths:
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	both modified:   internal/inventory/awsfetcher/fetcher_ec2_instance.go

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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

[mergify]

This pull request has not been merged yet. Could you please review and merge it @kubasobon? 🙏