Update PhoneButton padding in MegaMenuLayout

[tiagov8]

Improve Contact Us as per @designbyalex

Full width is much better in mobile. The padding seems unconventional. I would expect at least 16px or 1 rem either side

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[designbyalex]

@tiagov8
I'm afraid I was unclear with my padding recommendation

at least 16px or 1 rem either side

My recommendation was under the assumption that the global padding for the page is 16px or 1 rem.
The button should match the rest of the content's padding.

Mobile button conventions: full-width on mobile if there is a single action, or 50/50 width if there are two actions. See examples below.

Figure: Facebook mobile app

Figure: Audible mobile app

[designbyalex]

@tiagov8
I've realised that the People page on the website has different global padding than the home page.

Figure: Look to be ~12px padding

Figure: 36 px padding

[tiagov8]

cc @griffenedge

Hi @designbyalex

I have updated this PR to also apply the padding to the header area (logo and main menu) + created a new PR to add the same padding to the content area: SSWConsulting/SSW.People#817

I know it is still inconsistent with SSW.com.au (px-4 VS px-8) but I think 36px padding is too much for the people page...

[designbyalex]

LGTM!