Add snapshot test about MoreMenu component

[hideokamoto]

Description

Related to progress on the issue -> Unit Testing Components #641

Added some unit test scripts for MoreMenu component.

How has this been tested?

Run unit test command.

 PASS  edit-post/components/header/more-menu/test/index.js
  MoreMenu
    ✓ should match snapshot (87ms)

Checklist:

• My code is tested.
• My code follows the WordPress code style.
• My code follows the accessibility standards.
• My code has proper inline documentation.

[gziolo]

There are a few coding style issues caught by Eslint, which were introduced in this PR:

/home/travis/build/WordPress/gutenberg/edit-post/components/header/more-menu/test/index.js
[0] 12:4 error There must be a space inside this paren space-in-parens
[0] 17:9 error There must be a space inside this paren space-in-parens
[0] 17:17 error There must be a space inside this paren space-in-parens
[0] 18:3 error There must be a space inside this paren space-in-parens
[0] 19:2 error There must be a space inside this paren space-in-parens
[0]
[0] ✖ 5 problems (5 errors, 0 warnings)
[0] 5 errors, 0 warnings potentially fixable with the --fix option.

They should be fixed before we can proceed.

[hideokamoto]

Oh, sorry. I've forgot to commit some update.
Now I've commit those update and pushed into the branch.

Thanks for reviewing :)

[gziolo]

All good now, thanks 👍