sync chain cancellation in Start a new sync chain may confuse users

[btlechowski]

Steps to Reproduce

1. Clean profile
2. Open brave://sync/
3. Click Start a new sync chain
4. Click Phone/Tablet
5. Click Cancel

Actual result:

1 . User clicks Cancel and gets Are you sure? dialog.

2. User thinks Yes, Cancel. User clicks Cancel as confirmation of the intent of cancelling the sync.
Alternative choice isn't helpful as it says Exit modal. User wonders what a modal is and if Are you sure? dialog is a modal.

Expected result:

The dialog should not confuse the user

Brave version (brave://version info)

Brave	0.59.20 Chromium: 72.0.3626.28 (Official Build) beta (64-bit)
Revision	997b1040b63bac324e815797ba52be0cd8f616ed-refs/branch-heads/3626@{#461}
OS	Windows

cc @bradleyrichter @rossmoody @brave/legacy_qa

[rebron]

Addressing the changes to dialog here to remove references to "modal". #2884

I think we still might need to be clearer with 'Cancel' and 'Exit' on that dialog though.

[srirambv]

@rebron we could just add Cancel Sync Setup on the QR/Code word modal instead of just Cancel. That makes it clear that you want to cancel creating a sync chain. The pop up modal cancel button is self explanatory that you want to cancel the modal and go back

[rebron]

@srirambv take a look at what @bradleyrichter proposed for #2884. We needed better wording for that dialog anyway. Should be clearer now.

[btlechowski]

Verification passed on

Brave	0.59.25 Chromium: 72.0.3626.53 (Official Build) beta (64-bit)
Revision	98434e6cd182d68ce396daa92e9c6310422e6763-refs/branch-heads/3626@{#620}
OS	Windows 7

Verification passed on

Brave	0.59.25 Chromium: 72.0.3626.53 (Official Build) beta (64-bit)
Revision	98434e6cd182d68ce396daa92e9c6310422e6763-refs/branch-heads/3626@{#620}
OS	Linux

Verified passed with

Brave	0.59.25 Chromium: 72.0.3626.53 (Official Build) beta(64-bit)
Revision	98434e6cd182d68ce396daa92e9c6310422e6763-refs/branch-heads/3626@{#620}
OS	Mac OS X