Update dependency terser to v5

[renovate]

This PR contains the following updates:

Package	Type	Update	Change
terser (source)	dependencies	major	4.8.0 -> 5.2.1
terser (source)	devDependencies	major	4.8.0 -> 5.2.1

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Release Notes

terser/terser

v5.2.1

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• The parse step now doesn't accept an ecma option, so that all ES code is accepted.
• Optional dotted chains now accept keywords, just like dotted expressions (foo?.default)

v5.2.0

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• Optional chaining syntax is now supported.
• Consecutive await expressions don't have unnecessary parens
• Taking the variable name's length (after mangling) into consideration when deciding to inline

v5.1.0

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• import.meta is now supported
• Typescript typings have been improved

v5.0.0

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• in operator now taken into account during property mangle.
• Fixed infinite loop in face of a reference loop in some situations.
• Kept exports and imports around even if there's something which will throw before them.
• The main exported bundle for commonjs, dist/bundle.min.js is no longer minified.

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Size Analysis Report

Affected Products

No changes between base commit (57739ae) and head commit (e4de9a4).

Test Logs

• Base (57739ae2): https://github.com/firebase/firebase-js-sdk/actions/runs/224342433
• Head (e4de9a46): https://github.com/firebase/firebase-js-sdk/actions/runs/224404956