feat(variables): Begin reading minidump memory for variables - #2035

When variable extraction is enabled, a SymCache-derived primitive or pointer size controls the minidump range read for a frame-offset variable. Although the memory accessor checks that the range exists, a successful range can be as large as the accepted dump and format!("{s:?}") materializes an uncapped, substantially larger String that is retained in the response, potentially exhausting worker memory.

Also found at:

• crates/symbolicator-native/src/symbolication/native.rs:256-258