Remove unnecessary copy from clipboard_get_files() #1104

Job	Run time
code formatting check	15s
cppcheck	18m 0s
min features with gcc	2m 39s
min features with g++	2m 48s
min features with clang	2m 11s
max features with gcc	3m 47s
max features with g++	2m 8s
max features with clang	3m 35s
max features with clang and AddressSanitized	2m 54s
max features with gcc and DEBUG	2m 28s
max features with gcc for 32-bit arch (legacy OS)	1m 57s
max features with g++ for 32-bit arch (legacy OS)	1m 36s
max features with clang for 32-bit arch (legacy OS)	1m 56s
	46m 14s

Provide feedback