fix(select): losing focus position when tabbing away after clicking inside multi select

[crisbeto]

Fixes the user's focus position being lost when they click to toggle an option inside a multi-select and then tab away.

Fixes #10900.

[jelbourn]

LGTM

[ngbot]

I see that you just added the pr: merge ready label, but the following checks are still failing:
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     1 pending code review

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[ngbot]

Hi @crisbeto! This PR has merge conflicts due to recent upstream merges.
Please help to unblock it by resolving these conflicts. Thanks!

[ngbot]

I see that you just added the pr: merge ready label, but the following checks are still failing:
     conflicts with base branch "master"
     1 pending code review

If you want your PR to be merged, it has to pass all the CI checks.

If you can't get the PR to a green state due to flakes or broken master, please try rebasing to master and/or restarting the CI job. If that fails and you believe that the issue is not due to your change, please contact the caretaker and ask for help.

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