Merge pull request #2213 from jnthntatum/v0.16.1

rollback: Opt-in to eager field lookup by default.

Incrementally check code point limit in NewSource

Avoids copying the full source if it is outside of the configured limit.

cross ref: cel-expr/cel-go#1302

PiperOrigin-RevId: 957218893

Remove invalid 'size' arg, use alignment as size.

PiperOrigin-RevId: 905243616

Add cel::Value::WrapMessageUnsafe.

Adds an unsafe version of wrap message that avoids copies but risks less obvious lifetime dependencies.

PiperOrigin-RevId: 833378293

Bump abseil and protobuf versions.

Use the `absl_nullable` style of nullability annotations.

PiperOrigin-RevId: 788564038

Suppress clang warning for direct memory write in value_variant.h.

PiperOrigin-RevId: 781114095

Update to cel-spec 0.23.0

PiperOrigin-RevId: 743693479

Move `CheckerOptions` to the `cel` namespace

PiperOrigin-RevId: 689503156

Update the default type provider (protobuf reflection impl) to return…

… a specific

type info instance instead of the generic one.

PiperOrigin-RevId: 534552333

Merge pull request #155 from google/cpp-sync

Internal change