fix(bootutil): correct copy size when bootstrapping and swapping with…#2553

TomLier wants to merge 1 commit intomcu-tools:mainmcu-tools/mcuboot:mainfrom

TomLier:bugfix/incorrect_copy_size_when_bootstrapping_and_swap_using_moveTomLier/mcuboot:bugfix/incorrect_copy_size_when_bootstrapping_and_swap_using_moveCopy head branch name to clipboard