fix(bazel): Pin browsers for schematics

[kyliau]

Pin versions for Chrome, ChromeDriver, Firefox, and GeckoDriver.

https://github.com/bazelbuild/rules_typescript/blob/c09bc740230ce0fbf3ca92b6c8755da577ef1de2/internal/karma/browser_repositories.bzl

This is a temporary workaround until fix lands in web_testing.

This change requires Angular 8.0.0-beta.6 and above

PR closes #28724

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• The commit message follows our guidelines: https://github.com/angular/angular/blob/master/CONTRIBUTING.md#commit
• Tests for the changes have been added (for bug fixes / features)
• Docs have been added / updated (for bug fixes / features)

PR Type

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• Bugfix
• Feature
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What is the current behavior?

Issue Number: N/A

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Does this PR introduce a breaking change?

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• No

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