feat(telemetry) add Kong router flavor

[rainest]

What this PR does / why we need it:

Includes the router flavor in reports.

Special notes for your reviewer:

Tests normally can't run telemetry against a real instance, so an example with that flipped in KONG_TEST_EXPRESSION_ROUTES=true KONG_TEST_CLUSTER=kind:kind GOFLAGS="-tags=integration_tests" dlv test ./test/integration

(dlv) p cfg["router_flavor"]
interface {}(string) "traditional"
(dlv) n
> github.com/kong/kubernetes-ingress-controller/v2/internal/manager/telemetry.SetupAnonymousReports() ./internal/manager/telemetry/reports.go:82 (PC: 0x3e0a70a)
    77:		kongDB, ok := cfg["database"].(string)
    78:		if !ok {
    79:			return nil, fmt.Errorf("malformed database configuration found in Kong client root")
    80:		}
    81:		routerFlavor, ok := cfg["router_flavor"].(string)
=>  82:		if !ok {
    83:			// version to old to use router flavor, de facto traditional
    84:			routerFlavor = "traditional"
    85:		}
    86:	
    87:		fixedPayload := Payload{
(dlv) p ok
true
...
(dlv) p fixedPayload
github.com/kong/kubernetes-telemetry/pkg/types.ProviderReport [
	"v": "NOT_SET", 
	"kv": "3.3.1", 
	"db": "off", 
	"r": "traditional", 
	"id": github.com/google/uuid.UUID [100,208,215,11,47,138,78,62,175,54,171,192,93,253,54,188], 
]

PR Readiness Checklist:

Complete these before marking the PR as ready to review:

• the CHANGELOG.md release notes have been updated to reflect any significant (and particularly user-facing) changes introduced by this PR

[codecov]

Codecov Report

Attention: 4 lines in your changes are missing coverage. Please review.

Comparison is base (be62bf7) 77.8% compared to head (aaa811a) 77.6%.

Additional details and impacted files

@@           Coverage Diff           @@
##            main   #4762     +/-   ##
=======================================
- Coverage   77.8%   77.6%   -0.2%     
=======================================
  Files        163     163             
  Lines      18526   18532      +6     
=======================================
- Hits       14416   14399     -17     
- Misses      3305    3322     +17     
- Partials     805     811      +6     

Files	Coverage Δ
internal/manager/telemetry/reports.go	47.6% <33.3%> (-1.5%)	⬇️

... and 9 files with indirect coverage changes

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[czeslavo]

I think that's not exactly what Konnect expected from us (it was about the UI side requiring some way to tell if a route we populate in Konnect is expression or traditional and we concluded it can be easily derived from the route itself).

Probably having telemetry for this won't hurt us and can be useful in the future. Worth to note though that we already have telemetry for tracking the feature gates so the ExpressionsRoutes feature is kinda tracked even without this.

[rainest]

I expect we'll remove the feature flag (GA support for controller-managed expression routes) before the gateway removes traditional (if it does at all), so it'll be useful later.

Also removed a rather unhelpful log. Failures due to the (unfortunately very touchy) expected value not matching looked like:

     telemetry_test.go:82: 
        	Error Trace:	/home/runner/work/kubernetes-ingress-controller/kubernetes-ingress-controller/test/envtest/telemetry_test.go:82
        	Error:      	Condition never satisfied
        	Test:       	TestTelemetry
    telemetry_test.go:85: failed to remove stanza "id" from report: stanza "id=" not found in report: 

Between not having a message on the Eventually and empty reports apparently being normal (not sure why, but they do show up) at the end of the test, I was very confused searching for why the changes here made part of the static report "disappear".

If we break it again, we'll now see:

    telemetry_test.go:82: 
        	Error Trace:	/tmp/ingress-controller/test/envtest/telemetry_test.go:82
        	Error:      	Condition never satisfied
        	Test:       	TestTelemetry
        	Messages:   	telemetry report never matched expected value