Fetch metadata via RPC instead of relying on the Friendbot response

[Shaptic]

When SKIP_TXMETA is enabled on a Horizon instance (like SDF's), the metadata isn't available in the friendbot response, either. This means we need to rely on a different source of metadata, so we fetch the transaction from RPC, instead.

[github-actions]

Size Change: +25.3 kB (+0.05%)

Total Size: 49.7 MB

Filename	Size	Change
dist/stellar-sdk-minimal.js	6.85 MB	+4.25 kB (+0.06%)
dist/stellar-sdk-minimal.min.js	5.34 MB	+2.09 kB (+0.04%)
dist/stellar-sdk-no-axios.js	6.85 MB	+4.25 kB (+0.06%)
dist/stellar-sdk-no-axios.min.js	5.34 MB	+2.09 kB (+0.04%)
dist/stellar-sdk-no-eventsource.js	7.11 MB	+4.25 kB (+0.06%)
dist/stellar-sdk-no-eventsource.min.js	5.55 MB	+2.09 kB (+0.04%)
dist/stellar-sdk.js	7.11 MB	+4.25 kB (+0.06%)
dist/stellar-sdk.min.js	5.55 MB	+2.09 kB (+0.04%)

_{compressed-size-action}