Fix for broken specs in ApplicationHelper::Dialogs

[eclarizio]

Some specs started breaking on the EUWE backport of ManageIQ/manageiq#14240 and that's because the model logic was changed to include 'none' or 'choose' now instead of the view needing to do it. There was a helper that was missed, and I think the original classic UI PR didn't have the test failure because the model change wasn't merged yet.

This should fix that by relying on the model to provide 'none' values instead of helper trying to do it. It removes some unnecessary logic in the helper and cleans up the tests a little bit as well.

https://bugzilla.redhat.com/show_bug.cgi?id=1428133

Note this does not need to be backported because I found it on the EUWE backport and made the necessary changes there already and am just forwarding it here.

@h-kataria You merged the earlier related classic UI component PR for the above mentioned PRs, so I'm assigning you here as well, please re-assign if this isn't correct!
/cc @gmcculloug

@miq-bot assign @h-kataria

[miq-bot]

Checked commits eclarizio/manageiq-ui-classic@00d3031~...966e0cd with ruby 2.2.6, rubocop 0.47.1, and haml-lint 0.20.0
4 files checked, 6 offenses detected

spec/services/ansible_tower_job_template_dialog_service_spec.rb

• ❕ - Line 76, Col 121 - Metrics/LineLength - Line is too long. [189/120]
• ❕ - Line 77, Col 121 - Metrics/LineLength - Line is too long. [179/120]

spec/services/orchestration_template_dialog_service_spec.rb

• ❕ - Line 127, Col 121 - Metrics/LineLength - Line is too long. [163/120]
• ❕ - Line 197, Col 121 - Metrics/LineLength - Line is too long. [240/120]
• ❕ - Line 61, Col 121 - Metrics/LineLength - Line is too long. [167/120]
• ❕ - Line 76, Col 121 - Metrics/LineLength - Line is too long. [167/120]

[romanblanco]

Tested in UI, works fine 👍