fix: improve send logic

[im-adithya]

Has some chores + performance improvements related to Send logic

6bb297c: Removes duplication regarding fixed amount invoices

8608c91: Fixes comment by not allowing if commentAllowed is 0

7df77e8: Sends directly to lnurl-pay since currently we are fetching lnurl details twice

2760058: Minor naming change as originalText was looking ugly

5c93c37: This is to make Send.tsx look more readable and also helps this PR to make a new screen for manual entering

05b5dab: Replaces Amount button text with Manual (and also replaces icon)

next 6 commits - Described in #307

fedd1a3: We were passing receiver and invoice to Receiver component for no reason, so I stopped passing that when there's an invoice, so now we do that only when there's an lnurl (we can actually unify that + recipientIdentifier, but will improve that in liightning-tools PR)

[im-adithya]

This is just a first step. We can improve this further once we use lightning-tools as described in #207, but will tackle that after the release cc @rolznz