envoy: update to v1.19.3

[shashankram]

Description:
Updates Envoy to v1.19.3 which include the latest security
patch.

Note: Update to v1.20+ is blocked due to
envoyproxy/envoy#20113

Testing done:
CI

Affected area:

Functional Area
Other	[X]

Please answer the following questions with yes/no.

1. Does this change contain code from or inspired by another project? no

   • Did you notify the maintainers and provide attribution?

2. Is this a breaking change? no

3. Has documentation corresponding to this change been updated in the osm-docs repo (if applicable)? Will be updated after this change is merged.

[codecov-commenter]

Codecov Report

Merging #4564 (e3f379e) into main (f83b8a7) will decrease coverage by 0.17%.
The diff coverage is 46.55%.

@@            Coverage Diff             @@
##             main    #4564      +/-   ##
==========================================
- Coverage   69.20%   69.03%   -0.18%     
==========================================
  Files         216      217       +1     
  Lines       14660    14760     +100     
==========================================
+ Hits        10146    10189      +43     
- Misses       4463     4519      +56     
- Partials       51       52       +1     

Flag	Coverage Δ
unittests	69.03% <46.55%> (-0.18%)	⬇️

Flags with carried forward coverage won't be shown. Click here to find out more.

Impacted Files	Coverage Δ
pkg/injector/iptables.go	100.00% <ø> (ø)
pkg/injector/patch.go	73.37% <13.63%> (-10.09%)	⬇️
cmd/osm-healthcheck/osm-healthcheck.go	34.84% <34.84%> (ø)
pkg/injector/envoy_config.go	79.41% <100.00%> (ø)
pkg/injector/health_probes.go	100.00% <100.00%> (ø)
pkg/injector/webhook.go	88.30% <100.00%> (ø)
pkg/certificate/rotor/rotor.go	84.78% <0.00%> (-2.18%)	⬇️
pkg/crdconversion/crdconversion.go	74.81% <0.00%> (+4.44%)	⬆️

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