Update Rust crate jemalloc_pprof to 0.8 (#36884)

This PR contains the following updates:

| Package | Type | Update | Change |
|---|---|---|---|
| [jemalloc_pprof](https://crates.io/crates/jemalloc_pprof) ([source](https://redirect.github.com/polarsignals/rust-jemalloc-pprof)) | workspace.dependencies | minor | `0.6` -> `0.8` |

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GitOrigin-RevId: 1dd2a6ecac028326cd3b85982706f3e833cb209d

Author: convex-renovate-runner[bot]

Cargo.lock

@@ -145,7 +145,7 @@ hyper = "1.3.1"
 hyper-util = { version = "0.1.5", features = [ "server-graceful", "tokio" ] }
 imbl = "5.0.0"
 itertools = "0.14"
-jemalloc_pprof = "0.6"
+jemalloc_pprof = "0.8"
 jsonschema = "0.30"
 levenshtein_automata = "0.2.1"
 libc = "0.2"