fix[x-google-ignore-list]: updated the link to devtools ignore plugin

[hoxyq]

Changes proposed in this pull request:

• Updates the link to devtools-ignore-plugin.ts, which sources were moved after https://github.com/angular/angular-cli/commit/466d86dc8d3398695055f9eced7402804848a381

[google-cla[bot]]

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[chrome-devrel-infra[bot]]

:white_check_mark: Preview (static) for commit 1152824ea711441f3d87bf57ad76b0c022b36dee available at https://pr-6608-static-dot-dcc-staging.uc.r.appspot.com/.

The following pages likely changed with this PR:

• https://pr-6608-static-dot-dcc-staging.uc.r.appspot.com/articles/x-google-ignore-list/