Use colored brave talk icon when there already opened tab for brave talk

[simonhong]

Test plan

1. Fresh install
2. Ensure sidebar is showing (or enable if needed)
3. Click Brave talk icon on the sidebar
4. Brave Talk icon in sidebar should change from gray outline to a colored outline
5. Open another talk.brave.com link in another tab
6. Verify the Brave Talk sidebar button cycles between both pages
7. Close both Brave Talk tabs
8. Verify Brave Talk sidebar icon is back to gray outline

Description

Like below image, brave talk icon should be colored when browser has tab that loads brave talk at least one.

If browser doesn't include brave talk tab, icon will not be colored one.

[stephendonner]

Verified PASSED using

Brave	1.37.36 Chromium: 98.0.4758.87 (Official Build) nightly (64-bit)
Revision	e4cd00f135fb4d8edc64c8aa6ecbe7cc79ebb3b2-refs/branch-heads/4758@{#1002}
OS	Windows 10 Version 21H2 (Build 19044.1466)

Steps:

1. installed 1.37.36
2. loaded brave://flags
3. set Enable Sidebar to Enabled
4. clicked Relaunch
5. loaded talk.brave.com (1), nbcnews.com, and talk.brave.com (2) in tabs
6. confirmed the Brave Talk icon changed to its colored version
7. clicked on the nbcnews.com (middle) tab
8. clicked on the Brave Talk icon in Sidebar
9. confirmed I cycled to the right, to the talk.brave.com (2) tab
10. clicked it again
11. confirmed I cycled back to the left, to the original talk.brave.com (1) tab
12. closed both Brave Talk tabs
13. confirmed the Brave Talk icon went back to gray

step 2	step 6	step 9	step 11	step 13

light mode:

---

Verified PASSED using

Brave	1.37.91 Chromium: 99.0.4844.51 (Official Build) beta (x86_64)
Revision	d537ec02474b5afe23684e7963d538896c63ac77-refs/branch-heads/4844@{#875}
OS	macOS Version 12.3 (Build 21E230)

Steps:

1. installed 1.37.91
2. loaded talk.brave.com (1), nbcnews.com, and talk.brave.com (2) in tabs
3. confirmed the Brave Talk icon changed to its colored version
4. clicked on the nbcnews.com (middle) tab
5. clicked on the Brave Talk icon in Sidebar
6. confirmed I cycled to the right, to the talk.brave.com (2) tab
7. clicked it again
8. confirmed I cycled back to the left, to the original talk.brave.com (1) tab
9. closed both Brave Talk tabs
10. confirmed the Brave Talk icon went back to gray

step 3	step 6	step 8	step 10

dark mode:

---

Verification passed on

Brave	1.37.95 Chromium: 99.0.4844.74 (Official Build) beta (64-bit)
Revision	fee9a47e86e981802390cb0d41c5ed7ea93c4f6f-refs/branch-heads/4844@{#1060}
OS	Ubuntu 18.04 LTS

confirmed the Brave Talk icon changed to its colored version

confirmed I cycled to the right, to the talk.brave.com (2) tab

confirmed I cycled back to the left, to the original talk.brave.com (1) tab

confirmed the Brave Talk icon went back to gray