Improve Send Error Sheet UX

[ovitrif]

I fixed the toast message in this PR but the error sheet message is also misleading, I will remove in next PR, then on this error screen we'll have parity with iOS:

That screen needs work on both platforms. Design has some improvements to status quo but needs to be adjusted somewhat. For LN payments "Transaction" is not accurate, should be "Payment". And we should try to show a user actionable error description as well as we can.

Originally posted by @pwltr in #825 (comment)

[jvsena42]

Follow-up: trigger a network-graph reset on repeated RouteNotFound from "Try again"

Splitting this out from the RGS network-graph health-check work (startup-side fix tracked separately).

Context / root cause: A decayed local RGS network graph causes PaymentFailureReason.ROUTE_NOT_FOUND even when the wallet has healthy channels and outbound liquidity. A real support case showed a graph at 4,071 nodes / 16,445 channels vs a full snapshot's ~6,567 / 36,921 (~55% of channels missing); the router found zero paths and even Wallet of Satoshi was unroutable despite 222k sats outbound. RGS deltas can't self-heal this — channels LDK pruned locally never come back via delta sync; only a graph wipe + full re-download fixes it.

Proposed follow-up here (send error sheet / "Try again"):

• When a Lightning payment fails with ROUTE_NOT_FOUND, count failures across distinct payees within a session.
• On a small threshold (and only when the local graph looks implausibly small), surface a recovery path from the "Try again" action that wipes + re-syncs the network graph before retrying, reusing the same reset mechanism added for the startup health check (LightningService.resetNetworkGraph + VSS network_graph delete, guarded against repeated wipes when RGS snapshot timestamp hasn't advanced).
• A single ROUTE_NOT_FOUND must NOT wipe (it's often just lack of liquidity) — only repeated failures combined with an implausibly small graph.

Being handled now (not here): startup-time graph-plausibility floor (mainnet-gated, channel-count based) with auto-wipe + loop guard, and a manual "reset network graph" option on the Recovery Mode screen.