chore(ci): pin symbolic-common

[lrstewart]

Release Summary:

Description of changes:

The Rust CI is failing with:

error[E0599]: no method named `is_none_or` found for enum `Option` in the current scope
  --> /home/runner/.cargo/registry/src/index.crates.io-6f17d22bba15001f/symbolic-common-12.14.0/src/path.rs:57:32
   |
57 |             return path.get(2).is_none_or(is_windows_separator);
   |                                ^^^^^^^^^^ help: there is a method with a similar name: `is_none`
For more information about this error, try `rustc --explain E0599`.
error: could not compile `symbolic-common` (lib) due to previous error
warning: build failed, waiting for other jobs to finish...

Looks like one of our dependencies, "symbolic", started using the is_none_or in their latest release: getsentry/symbolic@0ba5f9c That was stabilized in 1.82.0.

Unfortunately, 1.82.0 is only 4.5 months old, and we have a policy of maintaining an MSRV at least 6mo old. So pin symbolic for another 1.5 months.

I did bump our toolchain to 1.81.0 though, which is exactly 6 months old.

Testing:

CI now passes, specifically "Standard Workspace Tests" in the generate action.

By submitting this pull request, I confirm that my contribution is made under the terms of the Apache 2.0 license.