Create new watch pop-up select is not being announced in screenreader

[bhavyarm]

Kibana version: 6.3.0 BC6

Browser version: chrome latest

Browser OS version: OS x

Original install method (e.g. download page, yum, from source, etc.): from staging

Describe the bug: Create new watch is not being announced by screenreader. So non-sighted user doesn't know that he is on a select pop-up box for creating new watches. Only the options are being read-out.

Steps to reproduce:

1. Use voiceover and navigate to watcher and create new watch
2. Create new watch is not announced by screenreader. Only threshold alert and advanced watch creation is announced.

Expected behavior: Screenreader needs to announce that user is on create new watch pop-up selection box.

Screenshots (if relevant):
Not announced:

Element is missing create new watch label(?):

[cjcenizal]

@elastic/kibana-management The control used for creating a new watch seems a little tough to control from an accessibility perspective because it's using ui-select. From a usability perspective, it also seems very unusual because the button turns into an input once you select it. I don't think I've seen this before -- and I'm unsure how we could communicate this to a screen reader.

I'd like to simplify this by replacing it with two separate buttons: "Create threshold alert" and "Create advanced watch". Objections?

[chrisronline]

@cjcenizal No objections! Sounds great!