feat(Symfony): Check cache.app is reachable before use

[Leiyks]

Description

This PR add a readyness check on the Symfony cache app in case the service is unavailable.
The absence of this check can be the cause for significant latency increase when the cache app is not available as we are fetching all the routes in that case.

[pr-commenter]

Benchmarks [ tracer ]

Benchmark execution time: 2025-12-03 16:02:16

Comparing candidate commit ea33259 in PR branch leiyks/APMS-17485 with baseline commit 2790073 in branch master.

Found 3 performance improvements and 0 performance regressions! Performance is the same for 191 metrics, 0 unstable metrics.

scenario:MessagePackSerializationBench/benchMessagePackSerialization

• 🟩 execution_time [-6.540µs; -5.580µs] or [-5.984%; -5.106%]

scenario:MessagePackSerializationBench/benchMessagePackSerialization-opcache

• 🟩 execution_time [-3.638µs; -2.342µs] or [-3.259%; -2.098%]

scenario:TraceSerializationBench/benchSerializeTrace

• 🟩 execution_time [-51.710µs; -42.990µs] or [-11.200%; -9.311%]

[codecov-commenter]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 61.69%. Comparing base (2790073) to head (ea33259).

Additional details and impacted files

@@            Coverage Diff             @@
##           master    #3514      +/-   ##
==========================================
- Coverage   61.81%   61.69%   -0.12%     
==========================================
  Files         142      142              
  Lines       12923    12923              
  Branches     1695     1695              
==========================================
- Hits         7988     7973      -15     
- Misses       4183     4196      +13     
- Partials      752      754       +2     

see 4 files with indirect coverage changes

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