Fix no-op outputs causing the plan renderer to skip the 'no changes' message

[liamcervante]

Currently, we are checking whether the output changes are empty before deciding to print the "no changes" message in the renderer. But, no-op changes do not print anything so any plan with no-op changes will make the renderer consider the output changes to be not empty so it won't print the nice message but then it also won't print any outputs.

This PR fixes this by computing the concrete output diffs earlier and then using them to decide whether to print the "no changes" message.

Fixes #32815

Target Release

1.4.1

Draft CHANGELOG entry

BUG FIXES

• Fix the plan renderer skipping the "no changes" messages when there are no-op outputs within the plan.

[github-actions]

Reminder for the merging maintainer: if this is a user-visible change, please update the changelog on the appropriate release branch.

[prowlaiii]

So, I'm unclear...
Is the lack of a summary message an issue or is that the new normal?
I certainly found it confusing and am going to drop back to 1.3.9.
(I've been a happy and enthusiastic Terraform user for several years and this is the first blocker I've encountered, so am looking forward to 1.4.1!)

[crw]

Note for history, the above question was answered in #32815 (comment)

[github-actions]

I'm going to lock this pull request because it has been closed for 30 days ⏳. This helps our maintainers find and focus on the active contributions.
If you have found a problem that seems related to this change, please open a new issue and complete the issue template so we can capture all the details necessary to investigate further.