Use std::optional if available. (#1625) #1998

Job	Run time
PSV.Linux.22.04.gcc9.Tests.CodeCov	10m 31s
PSV.Linux.22.04.gcc9.Cpplint	8m 35s
PSV.Linux.22.04.gcc11	8m 24s
PSV.MacOS14.Xcode15	3m 27s
PSV.iOS.MacOS13.Xcode15	15m 4s
PSV.iOS.MacOS15.Xcode16	10m 59s
PSV.iOS.MacOS14.Xcode15	7m 45s
PSV.Linux.22.04.gcc11.OLP_SDK_ENABLE_DEFAULT_CACHE=OFF	2m 34s
PSV.iOS.MacOS13.Xcode14	15m 21s
PSV.Win.VC2022	10m 0s
PSV.MacOS15.Xcode16	3m 4s
PSV.Linux.22.04.gcc9.OLP_SDK_ENABLE_DEFAULT_CACHE=OFF	2m 52s
PSV.Linux.latest.gcc14.OLP_SDK_ENABLE_DEFAULT_CACHE=OFF	2m 43s
PSV.Linux.22.04.gcc13	12m 53s
PSV.Linux.22.04.clang	9m 1s
PSV.MacOS13.Xcode15.x86_64	3m 36s
PSV.Linux.Android.22.04	6m 57s
PSV.Clang.Format.Checker	38s
PSV.Commit.Checker	0s
	2h 14m 24s

Provide feedback