Some batch sizes lead to corrupted files

[LoZio]

I created several batches. Using size=25 the resulting files are not well formed and cannot be aired.
See
flipperdevices/flipperzero-firmware#1540

(and not to open another issue since it's a trivial fix: zero fill the file number i.e. CAME_50_003 to be easier to read/find)

[BitcoinRaven]

I noticed this problem a while ago, what happened the flipper keeps sending endlessly, I thought it was one time thing, let me check whats going on, and i will try your fix

[BitcoinRaven]

file name fixed