feat(solana-wallet-snap): use shareable serialization in Solana snap

[Julink-eth]

Explanation

• Switch the Solana snap from local serialize / deserialize / Serializable to the shared helpers in @metamask/snap-networks-utils (WPN-1943).
• Delete packages/solana-wallet-snap/src/core/serialization/ and rewire every call site (state, interface context, cache, clients, confirmation UI) to the shared package.
• Cast serialize() results to Record<string, Json> at the three snap-API call sites that require an object (snap_createInterface, snap_updateInterface, snap_manageState). The shared helper is typed as Json; those values are always objects.
• Drop unused eslint-suppressions.json entries that pointed at the deleted local serialization files.
• No changelog entry: this is an internal rewire with no consumer-facing API change.

References

Checklist

• I've updated the test suite for new or updated code as appropriate
• I've updated documentation (JSDoc, Markdown, etc.) for new or updated code as appropriate
• I've communicated my changes to consumers by updating changelogs for packages I've changed
• I've introduced breaking changes in this PR and have prepared draft pull requests for clients and consumer packages to resolve them