fix: honor lookbackSeconds in monovertex and rust pipeline

[kohlisid]

Currently if the lookbackSeconds is specified in the spec, the metric lag reader does not honor that value and keeps using default

apiVersion: numaflow.numaproj.io/v1alpha1
kind: MonoVertex
metadata:
  name: simple-mono-vertex
spec:
  scale:
    lookbackSeconds: 90

Before change

skohli@macos-JQWR9T560R numaflow % kubectl logs simple-mono-vertex-mv-0-fovym -f | grep MYDEBUG
2024-12-05T01:01:55.057650Z  INFO numaflow_core::metrics: MYDEBUG LABEL "default" 120
2024-12-05T01:02:04.057950Z  INFO numaflow_core::metrics: MYDEBUG LABEL "default" 120

After

skohli@macos-JQWR9T560R numaflow % kubectl logs simple-mono-vertex-mv-0-pfevp -f | grep MYDEBUG
2024-12-05T01:02:55.514563Z  INFO numaflow_core::metrics: MYDEBUG LABEL "default" 90
2024-12-05T01:02:58.514440Z  INFO numaflow_core::metrics: MYDEBUG LABEL "default" 90

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 64.73%. Comparing base (05df886) to head (02cf4b9).
Report is 1 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #2258      +/-   ##
==========================================
- Coverage   64.75%   64.73%   -0.03%     
==========================================
  Files         345      345              
  Lines       41415    41465      +50     
==========================================
+ Hits        26819    26843      +24     
- Misses      13528    13554      +26     
  Partials     1068     1068              

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