fix: Fix components not rendering id prop

[diegohaz]

Closes #518

This PR fixes regressions introduced by #492 and #494, which made some components ignore the id prop.

@namjul Do you know if there are other components with the same issue?

Does this PR introduce a breaking change?

No

[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 33ecd00:

Sandbox	Source
inspiring-moon-p1chg	Configuration
priceless-wilbur-ovpjx	Issue #518

[codecov]

Codecov Report

Merging #520 into master will increase coverage by <.01%.
The diff coverage is 92.85%.

@@            Coverage Diff            @@
##           master    #520      +/-   ##
=========================================
+ Coverage    96.4%   96.4%   +<.01%     
=========================================
  Files          99      99              
  Lines        1500    1504       +4     
  Branches      476     480       +4     
=========================================
+ Hits         1446    1450       +4     
  Misses         54      54

Impacted Files	Coverage Δ
packages/reakit/src/Id/IdGroup.tsx	100% <100%> (ø)	⬆️
packages/reakit/src/Id/Id.tsx	100% <100%> (ø)	⬆️
packages/reakit/src/Rover/Rover.ts	94.11% <100%> (ø)	⬆️
packages/reakit/src/Tab/__utils.ts	100% <100%> (ø)	⬆️
packages/reakit/src/Tab/Tab.ts	92.85% <83.33%> (+0.54%)	⬆️

---

Continue to review full report at Codecov.

Legend - Click here to learn more
Δ = absolute <relative> (impact), ø = not affected, ? = missing data
Powered by Codecov. Last update d5e1e8f...ff98fee. Read the comment docs.

[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 ff98fee:

Sandbox	Source
eloquent-platform-d7pz0	Configuration
wonderful-bush-mpdrh	Issue #518

[ariakit-bot]

Deploy preview for reakit ready!

Built with commit ff98fee

https://deploy-preview-520--reakit.netlify.com

[siggirh]

With this change you can no longer use zero as a stopId since !stopId will always be false. :)

EDIT: Nm, didnt know the stopId had to be a string.