Add @supportSync parsing logic for Custom Function Sync

[hermanwenhe]

Thank you for your pull request!

Please add '[major]', '[minor]', or [patch] to the title to indicate the impact the change has on the code. Please also provide the following information.

---

Change Description:

Add @supportSync parsing logic for Custom Function Sync

1. Do these changes impact command syntax of any of the packages? (e.g., add/remove command, add/remove a command parameter, or update required parameters)
   No

2. Do these changes impact documentation? (e.g., a tutorial on https://learn.microsoft.com/office/dev/add-ins/overview/office-add-ins)
   No

If you answered yes to any of these please do the following:
> Include 'Rick-Kirkham' in the review
> Make sure the README file is correct

Validation/testing performed:

Manually tested with metadata parsing logic in Excel host app.

[millerds]

/azurepipelines run

[azure-pipelines]

Azure Pipelines successfully started running 1 pipeline(s).

[millerds]

/azurepipelines run

[azure-pipelines]

Azure Pipelines successfully started running 1 pipeline(s).

[MiaofeiWang]

It would be better to add some tests in https://github.com/OfficeDev/Office-Addin-Scripts/tree/9fb9b4a3be426f4d2a079c062cc5c483aa19c5c7/packages/custom-functions-metadata/test. Maybe we can do that in next PR.

[hermanwenhe]

It would be better to add some tests in https://github.com/OfficeDev/Office-Addin-Scripts/tree/9fb9b4a3be426f4d2a079c062cc5c483aa19c5c7/packages/custom-functions-metadata/test. Maybe we can do that in next PR.

Will do in future.

[hermanwenhe]

@millerds Can you help review and approve the latest iteration?

[millerds]

@millerds Can you help review and approve the latest iteration?

New policy changes prevent me from checking in over the SDL failure, which seems to happen with doing a cross fork PR (haven't figured out what to do about that yet). You may have to create a new PR directly in the repo (use the user/* branch name pattern used in OMR) instead of a fork.

[hermanwenhe]

@millerds Can you help review and approve the latest iteration?

New policy changes prevent me from checking in over the SDL failure, which seems to happen with doing a cross fork PR (haven't figured out what to do about that yet). You may have to create a new PR directly in the repo (use the user/* branch name pattern used in OMR) instead of a fork.

Can you add me as contributor? I need access to create branch in this repo.