Disable speech API on strict fingerprint blocking

[ghost]

Description

The speech API reveals language preferences on Windows 10. Please disable or spoof speech API when set to strict fingerprint blocking.

Steps to Reproduce

1. On Windows 10 go to https://browserleaks.com/javascript
2. The SpeechSynthesis section reveals the languages installed on your system.

Actual result:

SpeechSynthesis shows:
Microsoft David Desktop - English (United States)
Microsoft Zira Desktop - English (United States)
(My own language here. I want to keep secret.)

Expected result:

SpeechSynthesis should be disabled, or only show:
Microsoft David Desktop - English (United States)
Microsoft Zira Desktop - English (United States)

Reproduces how often:

Easily reproduced

Brave version (info found on brave://version)

Brave	1.20.103 Chromium: 88.0.4324.152 (Official Build) (64-bit)
Revision	6579930fc53b4dc589c042bec9d0a3778326974d-refs/branch-heads/4324@{#2106}
OS	Windows 10 OS Version 1809 (Build 17763.1757)

Version/Channel Information:

Other Additional Information:

Miscellaneous Information:

[pes10k]

Thank you for the bug report! Marking this as a dupe of #18062, where we'll track progress on this issue.