Mobile: UI bugs

[cvarley100]

Description

• Fixes UI not being reset when cancelling send via hardware back press
• Fixes Snapshot transition text cut-off
• Centres password input on delete account
• Update account info alert colour

Fixes #912
Fixes #910
Fixes #909
Fixes #908

Type of change

Please delete options that are not relevant.

• Bug fix (a non-breaking change which fixes an issue)

How Has This Been Tested?

Checklist:

Please delete items that are not relevant.

• My code follows the style guidelines for this project
• I have performed a self-review of my own code
• I have commented my code, particularly in hard-to-understand areas
• New and existing unit tests pass locally with my changes
• For changes to mobile that include native code (including React Native modules): I have verified that both iOS and Android successfully build in both Debug and Release modes

[laumair]

LGTM!