Move the cursor field in rpc.Server.getEvents to the right place

[Shaptic]

It's at the top level not in each event like pagingToken was.

[github-actions]

Size Change: +984 B (0%)

Total Size: 49.7 MB

Filename	Size	Change
dist/stellar-sdk-minimal.js	6.87 MB	+137 B (0%)
dist/stellar-sdk-minimal.min.js	5.35 MB	+109 B (0%)
dist/stellar-sdk-no-axios.js	6.87 MB	+137 B (0%)
dist/stellar-sdk-no-axios.min.js	5.35 MB	+109 B (0%)
dist/stellar-sdk-no-eventsource.js	7.11 MB	+137 B (0%)
dist/stellar-sdk-no-eventsource.min.js	5.55 MB	+109 B (0%)
dist/stellar-sdk.js	7.11 MB	+137 B (0%)
dist/stellar-sdk.min.js	5.55 MB	+109 B (0%)

_{compressed-size-action}