Fix translation icon is visible after installing g-translate extension

[simonhong]

This regression comes from aa8c67
Originally, TranslateIconView::UpdateImpl() was not called if
extension is installed.

Resolves brave/brave-browser#8082

Submitter Checklist:

• Submitted a ticket for my issue if one did not already exist.
• Used Github auto-closing keywords in the commit message.
• Added/updated tests for this change (for new code or code which already has tests).
• Verified that these changes build without errors on
  • Android
  • iOS
  • Linux
  • macOS
  • Windows
• Verified that these changes pass automated tests (unit, browser, security tests) on
  • iOS
  • Linux
  • macOS
  • Windows
• Verified that all lint errors/warnings are resolved (npm run lint)
• Ran git rebase master (if needed).
• Ran git rebase -i to squash commits (if needed).
• Tagged reviewers and labelled the pull request as needed.
• Request a security/privacy review as needed.
• Add appropriate QA labels (QA/Yes or QA/No) to include the closed issue in milestone
• Public documentation has been updated as necessary. For instance:
  • https://github.com/brave/brave-browser/wiki/Deviations-from-Chromium-(features-we-disable-or-remove)
  • https://github.com/brave/brave-browser/wiki/Proxy-redirected-URLs
  • https://github.com/brave/brave-browser/wiki/Fingerprinting-Protection-Mode
  • https://github.com/brave/brave-browser/wiki/Brave%E2%80%99s-Use-of-Referral-Codes
  • https://github.com/brave/brave-browser/wiki/Custom-Headers
  • https://github.com/brave/brave-browser/wiki/Web-compatibility-issues-with-tracking-protection
  • https://github.com/brave/brave-browser/wiki/QA-Guide

Test Plan:

Refer to STR in issue.

Reviewer Checklist:

• New files have MPL-2.0 license header.
• Request a security/privacy review as needed.
• Adequate test coverage exists to prevent regressions
• Verify test plan is specified in PR before merging to source

After-merge Checklist:

• The associated issue milestone is set to the smallest version that the
  changes has landed on.
• All relevant documentation has been updated.

[yrliou]

++

[simonhong]

Merged because lint, browser test failure in CI are all not related with this PR.

[kjozwiak]

Verification PASSED on macOS 10.15.3 x64 using the following build:

Brave	1.8.9 Chromium: 80.0.3987.132 (Official Build) nightly (64-bit)
Revision	fcea73228632975e052eb90fcf6cd1752d3b42b4-refs/branch-heads/3987@{#974}
OS	macOS Version 10.15.3 (Build 19D76)

• Verified the STR outlined under Appears broken translate button brave-browser#8082 (comment)
• ensured that the Translate icon appears in the URL when visiting a website in another locale
• ensured that the Translate icon displays a modal re: installing the translation extension
• ensured once the Google Translate extension was installed, the Translate icon isn't displayed
• ensured that the Translate button re-appears on websites using another locale once the extension has been removed