Introduce convenient implicit operator string_view #5813

Job	Run time
Build Linux with -DFLATBUFFERS_NO_FILE_TESTS	26s
Build Linux (g++-13)	29s
Build Linux with out-of-source build location	14s
Build Linux (clang++-15)	33s
Build Linux C++ (11, g++-13)	32s
Build Linux C++ (11, clang++-15)	26s
Build Android (on Linux)	2m 28s
Build Linux C++ (14, g++-13)	30s
Build Linux C++ (14, clang++-15)	34s
Build Benchmarks (on Linux) (g++-13)	1m 6s
Build Linux C++ (17, g++-13)	1m 11s
Build Windows C++ (11)	3m 12s
Build .NET Windows	23s
Build Linux C++ (17, clang++-15)	26s
Build Windows C++ (14)	3m 18s
Check Generated Code (g++-13)	32s
Build .NET Windows (-p:UnsafeByteBuffer=true)	1m 21s
Build Linux C++ (20, g++-13)	32s
Build Windows C++ (17)	3m 37s
Build Linux C++ (20, clang++-15)	37s
Build Windows C++ (20)	5m 3s
Build Linux C++ (23, g++-13)	28s
Build Windows C++ (23)	5m 48s
Check Generated Code on Windows	4m 11s
Check Generated Code (clang++-15)	39s
Build Mac (universal build)	4m 42s
Build Mac (for Intel)	2m 46s
Build Windows 2019	3m 36s
Build Windows 2015	3m 3s
Build Windows 2017	4m 32s
Build Go	56s
Build Dart	36s
Build Java	19s
Build Kotlin Linux	1m 7s
Build Kotlin MacOS	5m 31s
Build Nim	24s
Build PHP	15s
Build Python	16s
Build Rust Linux	52s
Build Rust Windows	46s
Build Swift	1m 11s
Build Swift Wasm	1m 6s
Build TS	47s
release-digests	0s
provenance	0s
	1h 11m 21s

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