Compute page length in bytes in test_allpages_pagesize
Compute page length in bytes in test_allpages_pagesize

API:allpages assumes page length is in bytes.
site.encoding() is used to convert from unicode to bytes.

Bug: T85663
Change-Id: I2cb49ba31543d7c48c71f25e686e2e7ede1b0122

h4ck3rm1k3/pywikibot-core,valhallasw/pywikibot-core,magul/pywikibot-core,hasteur/g13bot_tools_new,wikimedia/pywikibot-core,VcamX/pywikibot-core,xZise/pywikibot-core,darthbhyrava/pywikibot-local,icyflame/batman,Darkdadaah/pywikibot-core,trishnaguha/pywikibot-core,PersianWikipedia/pywikibot-core,smalyshev/pywikibot-core,npdoty/pywikibot,Darkdadaah/pywikibot-core,npdoty/pywikibot,magul/pywikibot-core,jayvdb/pywikibot-core,h4ck3rm1k3/pywikibot-core,happy5214/pywikibot-core,jayvdb/pywikibot-core,emijrp/pywikibot-core,TridevGuha/pywikibot-core,hasteur/g13bot_tools_new,hasteur/g13bot_tools_new,happy5214/pywikibot-core,wikimedia/pywikibot-core