fix(examples): fix KeptnMetric in metrics example

[mowies]

for some reason, the keptnmetric doesn't work with the keptn provided range options

[sonarqubecloud]

Quality Gate passed

Issues
0 New issues
0 Accepted issues

Measures
0 Security Hotspots
0.0% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarCloud

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 74.71%. Comparing base (ff62ede) to head (19fcf93).
Report is 120 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #3667      +/-   ##
==========================================
+ Coverage   74.67%   74.71%   +0.03%     
==========================================
  Files         225      225              
  Lines       10131    10131              
==========================================
+ Hits         7565     7569       +4     
+ Misses       2196     2193       -3     
+ Partials      370      369       -1     

see 1 file with indirect coverage changes

Flag	Coverage Δ
certificate-operator	47.20% <ø> (ø)
component-tests	58.36% <ø> (+0.32%)	⬆️
lifecycle-operator	76.22% <ø> (ø)
metrics-operator	76.17% <ø> (ø)
scheduler	34.59% <ø> (ø)

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