config: rename IsGossipServer => IsListenServer

[cce]

Summary

As discussed in #6516 the config helper function name IsGossipServer() is confusing because it implies a connection to the "gossip service". It actually checks if algod has been configured to listen for incoming connections, whether or not the gossip service is enabled.

Test Plan

Name-only change, no code changed.

[codecov]

Codecov Report

❌ Patch coverage is 73.33333% with 4 lines in your changes missing coverage. Please review.
✅ Project coverage is 47.69%. Comparing base (a5d7ec2) to head (254877a).
⚠️ Report is 1 commits behind head on master.
✅ All tests successful. No failed tests found.

Files with missing lines	Patch %	Lines
daemon/algod/server.go	0.00%	3 Missing ⚠️
node/follower_node.go	0.00%	0 Missing and 1 partial ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##           master    #6525      +/-   ##
==========================================
- Coverage   47.85%   47.69%   -0.16%     
==========================================
  Files         662      655       -7     
  Lines       87940    87855      -85     
==========================================
- Hits        42082    41903     -179     
- Misses      43093    43180      +87     
- Partials     2765     2772       +7     

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