"Wide" widgets are no longer supported

[shaunandrews]

With the merge of MP6, the widgets component brought along a few !important styles that forced widgets to fit within their sidebar. While I was the one who did this, and think wide widgets are the devil, we'll need to allow widgets to break out of their sidebar as we always have.

[shaunandrews]

The patch above removes the !important styles that were overriding the widget width, fixes a missing border-bottom from widgets when dragged and expanded, and removes the extraneous 30px of width that were previously added to expanded widgets.

[SergeyBiryukov]

Related: ​https://irclogs.wordpress.org/chanlog.php?channel=wordpress-dev&day=2013-11-19&sort=asc#m732752

[azaozz]

In 26275:

Widgets:

• Remove the !important styles that were overriding the widget width when expanded.
• Fix missing border-bottom from widgets when dragged and expanded.

Props shaunandrews, see #26117.

[azaozz]

In 26277:

Widgets:

• Fix support for expanding (wide) widgets in the Inactive Widgets area.
• Remove resizing of the sidebars height.
• Stop removing unneeded "for" attributes from labels inside the widgets. Was a fix for IE6 odd behaviour.

See #26117.