feat: add comma value-delimiter to with argument in tool run args to allow for multiple arguments in with flag (#7909)
This is to address my own issue #7908
## Summary
This change makes use of the `clap` value_delimiter parser to populate
the `with` `Vec<String>` which currently can either only be empty or
with 1 value for each `--with` flag.
This makes use of the current code structure but allows for multiple
arguments with a single `--with` flag.
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## Test Plan
Can be tested with the following CLI:
```bash
target/debug/uv tool run --with numpy,polars,matplotlib ipython -c "import numpy;import polars;import matplotlib;"
```
And former behavior of multiple `--with` flags are kept
```bash
target/debug/uv tool run --with numpy --with polars --with matplotlib ipython -c "import numpy;import polars;import matplotlib;"
```
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Co-authored-by: Charlie Marsh <charlie.r.marsh@gmail.com>