ci: add focused PR benchmark labels #6613

Job	Run time
C++ API (coverage)	1m 3s
Rust/C++ FFI tests (tsan)	1m 57s
Rust/C++ FFI tests (asan)	2m 11s
Rust tests (miri)	1m 36s
Rust tests (tsan)	6m 33s
Rust tests (asan)	6m 56s
Mirror DuckDB to R2 / Resolve DuckDB version and check R2	7s
Mirror DuckDB to R2 / Mirror DuckDB ${{ matrix.archive }} to R2	-1s
DuckDB libraries available in R2	2s
Rust tests (coverage) (tests)	6m 41s
	27m 5s

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