feat(stellar-wallet-snap): use shared urlstruct

[Julink-eth]

Explanation

Replace the Stellar snap's local UrlStruct with the shared one from @metamask/snap-networks-utils, matching Solana and Tron.

• Call sites (config, buildUrl, PriceApiClient, SecurityAlertsApiClient, token-api structs) import UrlStruct from @metamask/snap-networks-utils.
• Local src/api/url.ts and url.test.ts are removed; validation lives in the shared package.
• Adds @metamask/snap-networks-utils and a tsconfig project reference.

References

• Related to WPN-1890
• Follows chore: move UrlStruct to shared lib (#174)

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

[stanleyyconsensys]

Approved , but plz do a publish preview to validate if you didnt

[Julink-eth]

@metamaskbot publish-preview

[github-actions]

Preview builds have been published. Learn how to use preview builds in other projects.

Expand for full list of packages and versions.

@metamask-previews/bitcoin-wallet-snap@2.0.1-preview-26d6c588
@metamask-previews/snap-networks-utils@1.0.0-preview-26d6c588
@metamask-previews/solana-wallet-snap@6.0.0-preview-26d6c588
@metamask-previews/stellar-wallet-snap@0.1.0-preview-26d6c588
@metamask-previews/tron-wallet-snap@3.1.0-preview-26d6c588