decrease font-weight to medium=500 for focused tab follow up to #8576

[rebron]

Description

#8576 sought to improve tab contrast. The font-weight for the focused tab is semi-bold = 600 but should be reduced to medium = 500.

Steps to Reproduce

1. Open browser and open a few tabs.
2. Notice weighting on focused tab is semi-bold

Actual result:

Expected result:

Slightly less bold

Reproduces how often:

Easily.

Brave version (brave://version info)

Version/Channel Information:

• Can you reproduce this issue with the current release? yes
• Can you reproduce this issue with the beta channel? yes
• Can you reproduce this issue with the nightly channel? yes

Other Additional Information:

• Does the issue resolve itself when disabling Brave Shields? n/a
• Does the issue resolve itself when disabling Brave Rewards? n/a
• Is the issue reproducible on the latest version of Chrome? n/a

Miscellaneous Information:

cc: @karenkliu

[GeetaSarvadnya]

To test this we would need a new build that is greater than 1.19.76

[btlechowski]

Verification passed on

Brave	1.19.78 Chromium: 87.0.4280.101 (Official Build) dev (64-bit)
Revision	9407c80213cda69c2b7abcb4fa8e3f74488f4956-refs/branch-heads/4280@{#1807}
OS	Ubuntu 18.04 LTS

Verified that the font is less bold in 1.19.x
Dark mode
1.18.x

1.19.x

Light mode
1.18.x

1.19.x

---

Verified passed with

Brave | 1.19.79 Chromium: 87.0.4280.141 (Official Build) dev (x86_64)
-- | --
Revision | 9f05d1d9ee7483a73e9fe91ddcb8274ebcec9d7f-refs/branch-heads/4280@{#2007}
OS | macOS Version 10.15.7 (Build 19H15)

Verified STR from description.
Confirmed Release 1.18.x tab title is slightly bolder than Dev 1.19.x tab title.

Light

Dark

---

Verification passed on

Brave | 1.19.82 Chromium: 88.0.4324.79 (Official Build) dev (64-bit)
-- | --
Revision | bd1e9353659b2491dac971226a973ca3b5684a14-refs/branch-heads/4324@{#1520}
OS | Windows 10 OS Version 2004 (Build 19041.685)

Verified STR from the description.
Confirmed Release 1.18.x tab title is slightly bolder than Dev 1.19.x tab title.

Light theme

Dark theme