macos crash reports are missing channel

[bridiver]

Description

Crash reports for beta, dev and nightly should have a channel

Steps to Reproduce

1. using a non-release channel go to brave://crash
2. go to brave://crashes and make sure that the crash has been sent
3. check backtrace for the crash id metadata

Actual result:

No channel value exists

Expected result:

channel is correctly populated

Reproduces how often:

always

Brave version (brave://version info)

since brave/brave-core#2634

Version/Channel Information:

beta, dev and nightly

• Can you reproduce this issue with the current release?
  no
• Can you reproduce this issue with the beta channel?
  yes
• Can you reproduce this issue with the dev channel?
  yes
• Can you reproduce this issue with the nightly channel?
  yes

[kjozwiak]

Moving issue into https://github.com/brave/brave-browser/milestone/92 👍

[LaurenWags]

Verified passed using macOS Mojave 10.14.6 x64

Brave	1.7.85 Chromium: 80.0.3987.162 (Official Build) dev (64-bit)
Revision	f2c5dd6138153bb0658091205bd1a1717f16081a-refs/branch-heads/3987@{#1034}
OS	macOS Version 10.14.6 (Build 18G3020)

• Verified STR from description
• Verified test plan from Fix mac crash reporting channel brave-core#5064 (comment)
  • crashed brave using brave://crash and noted the Crash Report ID
  • crashed brave using brave://gpucrash and noted the Crash Report ID

Checked and ensured that the crashes were reporting the correct channel:

Using brave://crash

Using brave://crashgpu