Copy kernel_configs.txt and kernel_version.txt to target_files.zip

Move extractKernelVersionAndConfigs before buildTargetFilesZip. The
intermediate kernel_configs.txt and kernel_version.txt will be copied to
the META subdirectory of target_files.zip

Test: Built soong's target_files.zip locally
Bug: 399788685
Change-Id: Iae3efce1958ebcf7e06169771e359a332120ece4