Flash-pay: Update charts for staging env

[x] ~~Staging charts are currently referencing external domain (api.staging.flashapp.me) rather than the internal name (api.flash.svc.cluster.local). Not sure if this may cause adverse effects over time~~ if it's not broken, don't fix it. We can open an issue if we find it's causing issues, otherwise we have higher priority items
[x] Point .well-known endpoint to flashapp.me to provide proper Lightning Addresses. Point staging to staging.flashapp.me, and ideally use a valid (production) certificate for integration testing with external wallets
[x] CORS error

lnflash / charts