[#957] [BZ#1712873] Prevent migration task info popovers with long error messages from being pushed off the screen

[mturley]

Fixes #957.
https://bugzilla.redhat.com/show_bug.cgi?id=1712873

The history of .popover max-width continues...

• In core bootstrap, popover max-width is set to 220px.
• This caused long errors to run over the borders of the popover box, so we fixed that by setting max-width to none in [3579] Long string overflow resolved by removing popover max-width property #580.
• I went to remove our max-width: none and found that around the same time, manageiq-ui-classic added the same max-width: none for all popovers to fix a similar issue: Improve per provider settings ui manageiq-ui-classic#2978, so that was still taking effect even without our override.
• Of course, now we find max-width: none here causes longer errors to run off the screen.

I set the max-width of these specific task info popovers to a sensible 450px in this PR, which should be wide enough to prevent the first issue and narrow enough to prevent the second one.

Maybe we're done now?

This fix can be tested with the database called long-task-error from my collection, which has a plan "rhv-vddk" containing the long error shown in the screenshots below.

Screens

Popover with the original max-width: 220px from bootstrap:

Popover with max-width: none:

Popover with max-width: 450px:

[miq-bot]

Checked commit mturley@9c259e4 with ruby 2.3.3, rubocop 0.69.0, haml-lint 0.20.0, and yamllint 1.10.0
0 files checked, 0 offenses detected
Everything looks fine. 🍰

[simaishi]

Hammer backport details:

$ git log -1
commit b9701aae59a6b8660a6a6637d939fc19a6ef4a91
Author: Milan Zázrivec <[email protected]>
Date:   Fri May 24 10:00:12 2019 +0200

    Merge pull request #962 from mturley/957-plan-details-popover-width-fix
    
    [#957] [BZ#1712873] Prevent migration task info popovers with long error messages from being pushed off the screen
    
    (cherry picked from commit b027796cac45cedf0f8e51e1f7c03b4f48c5bef6)
    
    Fixes https://bugzilla.redhat.com/show_bug.cgi?id=1713732