fix realtime fetcher small skips feature

[ayrat555]

If indexing is started from scratch, realtime fetcher
tries to index large ranges of blocks. For example, 5..1852044.
It produces errors like
failed to fetch: :emfile. Block will be retried by catchup indexer

This PR limits the number of blocks to 10

Changelog

• fix realtime fetcher small skips feature

[coveralls]

Pull Request Test Coverage Report for Build 9f292f06-a3ba-48c1-be0e-1398eeea1271

• 3 of 3 (100.0%) changed or added relevant lines in 1 file are covered.
• 76 unchanged lines in 8 files lost coverage.
• Overall coverage decreased (-1.09%) to 75.382%

---

Files with Coverage Reduction	New Missed Lines	%
apps/block_scout_web/lib/block_scout_web/controllers/chain/market_history_chart_controller.ex	1	78.57%
apps/ethereum_jsonrpc/lib/ethereum_jsonrpc/http/httpoison.ex	1	0.0%
apps/ethereum_jsonrpc/test/support/ethereum_jsonrpc/case/parity/http_websocket.ex	1	0.0%
apps/indexer/lib/indexer/transform/addresses.ex	1	75.0%
apps/indexer/lib/indexer/block/fetcher.ex	3	83.13%
apps/ethereum_jsonrpc/test/support/ethereum_jsonrpc/web_socket/case/parity.ex	4	0.0%
apps/ethereum_jsonrpc/lib/ethereum_jsonrpc/http.ex	12	52.0%
apps/ethereum_jsonrpc/lib/ethereum_jsonrpc/web_socket/web_socket_client.ex	53	11.25%

Totals
Change from base Build ad5ef839-68f3-4d4d-a043-1dd7f6b83867:	-1.09%
Covered Lines:	5230
Relevant Lines:	6938

---

💛 - Coveralls