inconsistent deprecation messaging for use_deprecated_pex_binary_run_semantics

[tdyas]

With Pants v2.13.0a1, not having the use_deprecated_pex_binary_run_semantics config displays:

15:44:49.52 [WARN] DEPRECATED: the option --use-deprecated-pex-binary-run-semantics defaulting to true is scheduled to be removed in version 2.14.0.dev1.

Currently, running a `pex_binary` by default will not include the source files in the PEX, and will instead put them in a temporary sandbox.

In Pants 2.14, the default will change to instead build the PEX like you had run the `package` goal, and then execute that PEX. This is more consistent and intuitive behavior.

To fix this deprecation, explictly set `use_deprecated_pex_binary_run_semantics` in the `[GLOBAL]` section of `pants.toml`. Set it to `true` to use the "old" behavior. Set it to `false` to use the "new" behavior.

When set to `false`, you can still run the binary as before because you can now run on a `python_source` target. The simplest way to do this is to use `./pants run path/to/file.py`, which will find the owning `python_source`. Pants will run the file the same way it used to with `pex_binary` targets.

Setting the config to False then causes a different deprecation message to appear suggesting to remove the config option:

15:44:19.29 [WARN] DEPRECATED: option 'use_deprecated_pex_binary_run_semantics' in global scope is scheduled to be removed in version 2.15.0.dev0.

If `use_deprecated_pex_binary_run_semantics` is already set explicitly to `false`, simply delete the option from `pants.toml` because `false` is now the default.

If set to `true`, removing the option will cause `run` on a `pex_binary` to package and run the built PEX file. Additionally, the `pex_binary` must be referred to by its address. To keep the old `run` semantics, use `run` on the relevant `python_source` target.

The second config message should not appear until after 2.13.0 is released.

[Eric-Arellano]

Closed by #16108