Cherry-pick PR #10951

[KevinTCoughlin]

Pull request checklist

• Addresses an existing issue: Fixes #0000
• Include a change request file using $ yarn change

Description of changes

Cherry-pick of #10951 since the Partner team is still on Fabric 6.x.

Focus areas to test

• CI should pass.

Microsoft Reviewers: Open in CodeFlow

[msft-github-bot]

Hello @cliffkoh!

Because this pull request has the AutoMerge label, I will be glad to assist with helping to merge this pull request once all check-in policies pass.

Do note that I've been instructed to only help merge pull requests of this repository that have been opened for at least 8 hours. No worries though, I will be back when the time is right! 😉

p.s. you can customize the way I help with merging this pull request, such as holding this pull request until a specific person approves. Simply @mention me (@msft-github-bot) and give me an instruction to get started! Learn more here.

[KevinTCoughlin]

@msft-github-bot merge once CI succeeds.

[cliffkoh]

@msft-github-bot merge in 1 min

[msft-github-bot]

Hello @cliffkoh!

Because you've given me some instructions on how to help merge this pull request, I'll be modifying my merge approach. Here's how I understand your requirements for merging this pull request:

• I won't merge this pull request until after the UTC date Thu, 24 Oct 2019 01:31:49 GMT, which is in 1 minute

If this doesn't seem right to you, you can tell me to cancel these instructions and use the auto-merge policy that has been configured for this repository. Try telling me "forget everything I just told you".

[size-auditor]

Asset size changes

Project	Bundle	Baseline Size	New Size	Difference
office-ui-fabric-react	ShimmeredDetailsList	220.703 kB	220.702 kB	-1 bytes
office-ui-fabric-react	DetailsList	209.874 kB	209.873 kB	-1 bytes

 Over Tolerance (1024 B)  Over Baseline  Below Baseline  New   Removed 1 kB = 1000 B

Baseline commit: a1b40542de48fd2ab59b83ba9b76a9f0895e9e15 (build)