Advanced settings date format change doesn't propagate to Canvas workpads

[bhavyarm]

Kibana version: 6.7.0 BC2

Elasticsearch version: 6.7.0 BC2

Server OS version: darwin_x86_64

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: If user sets the time in advanced settings date format field - Canvas elements don't really get that change. They display in the basic default format: MMMM Do YYYY, HH:mm:ss.SSS

Steps to reproduce:

1. Go to advanced settings and change the date format to dddd, MMMM Do YYYY, h:mm:ss a
   which should display date as "Sunday, February 14th 2010, 3:25:50 pm"
2. Go to canvas and add a data table element to canvas
3. Add timefield as one of the fields -Canvas still displays it in the default format.

[elasticmachine]

Pinging @elastic/kibana-canvas

[crob611]

Closing this in favor of enhancment request #37436