tls_manager: port tls partial files handling back to v0.20.x-branch#10422

yyforyongyu merged 3 commits intolightningnetwork:v0.20.x-branchlightningnetwork/lnd:v0.20.x-branchfrom

mohamedawnallah:handle-partial-tls-files-v0.20.xmohamedawnallah/lnd:handle-partial-tls-files-v0.20.xCopy head branch name to clipboard