feat: add request processing total and request succeed total metrics

[ev1lQuark]

New Metrics:

1. RequestProcessingTotal: dubbo_provider_requests_processing_total, dubbo_provider_requests_processing_total
2. RequestSucceedTotal: dubbo_provider_requests_succeed_total, dubbo_provider_requests_succeed_total

[sonarcloud]

Kudos, SonarCloud Quality Gate passed!   

0 Bugs
0 Vulnerabilities
0 Security Hotspots
1 Code Smell

No Coverage information
0.0% Duplication

[codecov-commenter]

Codecov Report

Merging #2331 (ad55d34) into main (95b463b) will increase coverage by 0.16%.
The diff coverage is 82.19%.

❗ Current head ad55d34 differs from pull request most recent head 0c7ddbe. Consider uploading reports for the commit 0c7ddbe to get more accurate results

@@            Coverage Diff             @@
##             main    #2331      +/-   ##
==========================================
+ Coverage   44.10%   44.27%   +0.16%     
==========================================
  Files         294      295       +1     
  Lines       17890    17932      +42     
==========================================
+ Hits         7890     7939      +49     
+ Misses       9161     9148      -13     
- Partials      839      845       +6     

Impacted Files	Coverage Δ
filter/metrics/filter.go	73.91% <0.00%> (-11.09%)	⬇️
metrics/prometheus/after_invocation.go	69.23% <71.42%> (-25.06%)	⬇️
metrics/prometheus/before_invocation.go	77.77% <77.77%> (ø)
metrics/prometheus/reporter.go	73.33% <80.00%> (+20.00%)	⬆️
metrics/prometheus/common.go	45.68% <100.00%> (+16.09%)	⬆️
metrics/prometheus/metric_set.go	100.00% <100.00%> (ø)

... and 2 files with indirect coverage changes

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[chickenlj]

LGTM.