chore: the output format of az command was specified

[jacobbaek]

It is better to set output format.

Fixes #

Description
someone might specify the ouput format as table or yaml.
If then, this script will fail.
So I added the output format as json.

How was this change tested?
it works well.

Does this change impact docs?

• Yes, PR includes docs updates
• Yes, issue opened: #
• No

Release Note

[coveralls]

Pull Request Test Coverage Report for Build 11486913099

Warning: This coverage report may be inaccurate.

This pull request's base commit is no longer the HEAD commit of its target branch. This means it includes changes from outside the original pull request, including, potentially, unrelated coverage changes.

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• For a quick fix, rebase this PR at GitHub. Your next report should be accurate.

Details

• 0 of 0 changed or added relevant lines in 0 files are covered.
• No unchanged relevant lines lost coverage.
• Overall coverage remained the same at 97.866%

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Totals
Change from base Build 11486809298:	0.0%
Covered Lines:	36318
Relevant Lines:	37110

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💛 - Coveralls

[jacobbaek]

@tallaxes
Could you review this PR?

[tallaxes]

LGTM, thank you for the contribution! (and apologies for the delay in reviewing)