fix: disable Sentry session tracking

[oz-for-oss]

Closes #9717

Description

• Disable Sentry auto session tracking so crash reporting no longer sends normal app session lifecycle traffic.
• Clarify the Privacy page so Help improve Warp is scoped to analytics telemetry and product-required backend connections are not conflated with that toggle.
• Update crash reporting copy/schema description to say crash and internal error reports, and clarify it excludes app analytics and normal session tracking.

Linked Issue

• The linked issue is labeled ready-to-spec or ready-to-implement.
• Where appropriate, screenshots or a short video of the implementation are included below (especially for user-visible or UI changes).

Screenshots / Videos

Not captured; this is a small settings-copy change plus crash-reporting configuration change.

Testing

• cargo fmt --all
• cargo fmt --all -- --check
• git --no-pager diff --check
• CARGO_BUILD_JOBS=1 cargo check -p warp --features crash_reporting --lib
• CARGO_BUILD_JOBS=1 cargo clippy -p warp --features crash_reporting --lib -- -D warnings

Attempted CARGO_BUILD_JOBS=1 cargo test -p warp --features crash_reporting sentry_client_options_disable_auto_session_tracking twice, but the sandbox killed the warp lib-test rustc process with SIGKILL before any Rust test result was produced.

Agent Mode

• Warp Agent Mode - This PR was created via Warp's AI Agent Mode

CHANGELOG-BUG-FIX: Disabled normal Sentry session tracking and clarified Privacy settings copy around analytics versus crash/error reporting.