rpc: filter subscriptions' notifications by name

[AnnaShaleva]

Closes #1263

[codecov]

Codecov Report

Merging #1266 into master will increase coverage by 0.00%.
The diff coverage is 100.00%.

@@           Coverage Diff           @@
##           master    #1266   +/-   ##
=======================================
  Coverage   67.77%   67.77%           
=======================================
  Files         215      215           
  Lines       18297    18299    +2     
=======================================
+ Hits        12401    12403    +2     
  Misses       5238     5238           
  Partials      658      658           

Impacted Files	Coverage Δ
pkg/rpc/request/param.go	92.36% <ø> (ø)
pkg/rpc/client/wsclient.go	84.56% <100.00%> (ø)
pkg/rpc/server/subscription.go	96.96% <100.00%> (+0.19%)	⬆️

---

Continue to review full report at Codecov.

Legend - Click here to learn more
Δ = absolute <relative> (impact), ø = not affected, ? = missing data
Powered by Codecov. Last update e9d41c7...4ff3a9e. Read the comment docs.