test

Remove remnants of `/guides` directory #2220

Job	Run time
Build site and check links	57s
Check if code excerpts are up to date	21s
Validate Firebase configuration	19s
Analyze and test code examples (beta, false)	33s
Check if text can be replaced with site variables	26s
Analyze and test code examples (stable, false)	1m 47s
	4m 23s

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