Simplified `EsploraExt` API #5136

Job	Run time
Check WASM	42s
clippy_check	23s
Build and test (stable, true, --no-default-features)	2m 27s
Check no_std	26s
Build and test (stable, true, --all-features)	2m 47s
Build and test (1.63.0, --no-default-features)	3m 18s
Rust fmt	8s
Build and test (1.63.0, --all-features)	3m 29s
	13m 40s

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