Remove explicitly setting agent's reporter type

[pavolloffay]

Tchannel reporter has been removed in 1.18.0
The GRPC reporter was set as default in 1.11.0

This also helps with using OTEL based images since they do not expose --reporter.type flag.

[codecov]

Codecov Report

Merging #1168 into master will decrease coverage by 0.00%.
The diff coverage is 100.00%.

@@            Coverage Diff             @@
##           master    #1168      +/-   ##
==========================================
- Coverage   88.29%   88.28%   -0.01%     
==========================================
  Files          89       89              
  Lines        5501     5498       -3     
==========================================
- Hits         4857     4854       -3     
  Misses        474      474              
  Partials      170      170              

Impacted Files	Coverage Δ
pkg/deployment/agent.go	96.18% <100.00%> (-0.06%)	⬇️
pkg/inject/sidecar.go	94.68% <100.00%> (-0.06%)	⬇️
pkg/storage/cassandra_dependencies.go	100.00% <0.00%> (ø)

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[jpkrohling]

I'm OK with this change, but has this flag been deprecated? If not, it would be good to deprecate it now and set a date for removal.

[pavolloffay]

The flag hasn't been deprecated or removed, but there is only one reporter type and no current plans to add another one, hence we can use the default.

[jpkrohling]

From our operator's perspective, sure. But I mean that other people out there might be using this flag as well. Just removing that without deprecating will break them.

[pavolloffay]

How would it break them? The flag is still supported in Jaeger.

[jpkrohling]

Sorry, my bad. I thought that having this flag would cause an error with the new binaries.