fix(whl_library): avoid excessive report_progress() messages (#2280)

With the current behavior, we see really long progress messages in the
console like

```
Running whl_library.ResolveRequirement(foobar_pip_deps_regex, regex==2023.12.25     --hash=sha256:0694219a1d54336fd0445ea3\
82d49d36882415c0134ee1e8332afd1529f0baa5
<many more lines of --hash values>
```

This spams the console and isn't very useful.

To fix, only print up to the first white space, which captures the
important information
(e.g. "regex==2024.12.25") and is brief.

Closes #2206

CHANGELOG.md

@@ -42,6 +42,8 @@ A brief description of the categories of changes:
 * (whl_filegroup): Provide per default also the `RECORD` file
 * (py_wheel): `RECORD` file entry elements are now quoted if necessary when a
   wheel is created
+* (whl_library) truncate progress messages from the repo rule to better handle
+  case where a requirement has many `--hash=sha256:...` flags
 
 ### Added
 * (py_wheel) Now supports `compress = (True|False)` to allow disabling

python/private/pypi/whl_library.bzl

@@ -244,7 +244,10 @@ def _whl_library_impl(rctx):
 
         repo_utils.execute_checked(
             rctx,
-            op = op_tmpl.format(name = rctx.attr.name, requirement = rctx.attr.requirement),
+            # truncate the requirement value when logging it / reporting
+            # progress since it may contain several ' --hash=sha256:...
+            # --hash=sha256:...' substrings that fill up the console
+            op = op_tmpl.format(name = rctx.attr.name, requirement = rctx.attr.requirement.split(" ", 1)[0]),
             arguments = args,
             environment = environment,
             quiet = rctx.attr.quiet,