issue #4078 End passphrase button z index run gmail tests

[limonte]

This PR puts the end pp session in front of google chat popups on hover to improve UX:

CleanShot.2021-11-29.at.21.44.22.mp4

close #4078

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Also fixed a small issue with the encrypted subject's look:

before	after

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Also bumped puppeteer to v12.0.1 as live gmail tests were failing with v12.0.0 because of this issue: https://flowcrypt.semaphoreci.com/jobs/8c3c44f4-1ffc-412c-b73c-62b435a48d2a + fixed a flaky test with weird puppeteer issue typing 'ompose draftc' instead of 'compose draft'

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Tests (delete all except exactly one):

• Not worth testing

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To be filled by reviewers

I have reviewed that this PR... (tick whichever items you personally focused on during this review):

• addresses the issue it closes (if any)
• code is readable and understandable
• is accompanied with tests, or tests are not needed
• is free of vulnerabilities
• is documented clearly and usefully, or doesn't need documentation