Fixes Set-AzKeyVaultSecret to allow objects as Tags (Issue #8494)

[lwajswaj]

Fixes issue #8494 by forcing all values in Tags hashtable to be strings.

Checklist

• I have read the Submitting Changes section of CONTRIBUTING.md
• The title of the PR is clear and informative
• The appropriate change log has been updated
• The PR does not introduce breaking changes
• If applicable, the changes made in the PR have proper test coverage
• For public API changes to cmdlets:
  • the changes have gone through a cmdlet design review (Microsoft internal partners only)
  • the cmdlet markdown files were generated using the platyPS module

[lwajswaj]

Attempted to use methods exposed at "TagsHelper" but they didn't adjust properly as they are receiving Dictionary<string, string> to get a HashTable OR a hashtable to return a Dictionary<string,string>. Made more sense to just create a new extension method.

[maddieclayton]

@lwajswaj I think what makes the most sense here is to convert the Hashtable to a Dictionary<string, string> using https://github.com/Azure/azure-powershell-common/blob/84adc2e8e833a22caa8ea714cd5c367e63da227c/src/ResourceManager/Version2016_09_01/Tags/TagsConversionHelper.cs#L47, then convert that dictionary back to a Hashtable using https://github.com/Azure/azure-powershell-common/blob/84adc2e8e833a22caa8ea714cd5c367e63da227c/src/ResourceManager/Version2016_09_01/Tags/TagsConversionHelper.cs#L82. This should do exactly what your code is doing, and will guarantee that KeyVault works the exact same as other cmdlets in our repo that convert between Hashtable and Dictionary<string, string>. I believe that this cmdlet fails where others do not because most services accept the Dictionary<string, string> rather than a Hashtable, so we are doing the CreateTagDictionary call which casts all tag keys and values to strings for all other cmdlet calls.

[lwajswaj]

Hey @maddieclayton, I think updating "ConvertToDictionary" with the logic I just pushed (it's basically based on your recommendation) it's better as I see it's referenced 16 different times and each one of them is a possible issue if the passed hashtable doesn't contain all strings. In this way, we prevent other issues to occur.

[maddieclayton]

In my opinion, rather than fixing the KeyVault specific implementation, we should change the cmdlet to use the general implementation: https://github.com/Azure/azure-powershell-common/blob/84adc2e8e833a22caa8ea714cd5c367e63da227c/src/ResourceManager/Version2016_09_01/Tags/TagsConversionHelper.cs. I believe this already does what you are fixing in the KeyVault implementation.

If this is too much work, I can take over the PR - just let me know

[lwajswaj]

yeap, you are right. For this cmdlet to use general implementation, it's an easy fix. Just pushed the updates to do so

[maddieclayton]

Just to make this a little more simple I edited the change down to just the error handling of the Tag hashtable - should be good to go once CI passes!

[maddieclayton]

@lwajswaj Thanks for the contribution!!