Added exports for decorators missing from v7

[GeoffCoxMSFT]

Issue

v7 office-ui-fabric-react allows deep imports of withResponsiveMode and withViewport, but v7 @fluentui/react does not.
ODSP needs these exported in order to move to the modern import name.

Changes

-- exported withResponsiveMode and withViewport methods and types from @fluentui/react/Decorators

[msft-fluent-ui-bot]

It looks like this change to the 7.0 branch may not have been submitted to master yet. Now that version 8 has released, all changes must be submitted to the master branch first (except in emergencies or if the change is irrelevant to version 8).

Please do one of the following:

• If you've already created a PR to master, add a link to it
• If the change is irrelevant to version 8, add a comment explaining why
• Otherwise, create a PR to master with this same change, and add a link to it

After that, you can dismiss this review and remove the "needs cherry-pick" label (or ask a team member to help do so).

Want to avoid this in the future? Include text like "Cherry-pick of ####" in the PR description (where #### is the real master PR number).

These export no longer exist in master branch and are 7.0 only

[codesandbox-ci]

This pull request is automatically built and testable in CodeSandbox.

To see build info of the built libraries, click here or the icon next to each commit SHA.

Latest deployment of this branch, based on commit bdeb1a4:

Sandbox	Source
Fluent UI Button	Configuration
codesandbox-react-template	Configuration

[khmakoto]

Seems like you need to update the API files.

[size-auditor]

Asset size changes

Project	Bundle	Baseline Size	New Size	Difference
office-ui-fabric-react	office-ui-fabric-react-Decorators		24.575 kB	24.575 kB

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

Baseline commit: d905d75d002f5fe9a24774a7e19b8842d1162b75 (build)

[fabricteam]

Perf Analysis

No significant results to display.

All results

Scenario	Render type	7.0 Ticks	PR Ticks	Iterations	Status
BaseButton	mount	765	754	5000
Breadcrumb	mount	36210	35787	5000
Checkbox	mount	1298	1300	5000
CheckboxBase	mount	1106	1080	5000
ChoiceGroup	mount	4191	4170	5000
ComboBox	mount	771	758	1000
CommandBar	mount	6674	6755	1000
ContextualMenu	mount	12943	12858	1000
DefaultButton	mount	944	945	5000
DetailsRow	mount	3200	3185	5000
DetailsRowFast	mount	3195	3172	5000
DetailsRowNoStyles	mount	3006	3016	5000
Dialog	mount	1933	1934	1000
DocumentCardTitle	mount	1543	1566	1000
Dropdown	mount	2145	2127	5000
FocusTrapZone	mount	1451	1468	5000
FocusZone	mount	1550	1529	5000
IconButton	mount	1473	1461	5000
Label	mount	291	285	5000
Layer	mount	1649	1644	5000
Link	mount	368	381	5000
MenuButton	mount	1260	1241	5000
MessageBar	mount	1742	1767	5000
Nav	mount	2778	2800	1000
OverflowSet	mount	1221	1207	5000
Panel	mount	1261	1219	1000
Persona	mount	817	814	1000
Pivot	mount	1235	1238	1000
PrimaryButton	mount	1096	1085	5000
Rating	mount	6609	6661	5000
SearchBox	mount	1057	1076	5000
Shimmer	mount	2185	2170	5000
Slider	mount	1275	1271	5000
SpinButton	mount	4302	4273	5000
Spinner	mount	348	351	5000
SplitButton	mount	2700	2671	5000
Stack	mount	412	415	5000
StackWithIntrinsicChildren	mount	1447	1459	5000
StackWithTextChildren	mount	4041	4067	5000
SwatchColorPicker	mount	9004	9030	5000
TagPicker	mount	2454	2424	5000
TeachingBubble	mount	43179	43308	5000
Text	mount	344	357	5000
TextField	mount	1186	1160	5000
Toggle	mount	692	698	5000
button	mount	88	94	5000