test: align Home Run Derby live test with strict HTTP behavior

Update the invalid game ID test to expect MlbHttpError for the
live API's 400 response instead of treating it as a 404 result.

Also close the shared Mlb client during test cleanup.

Author: Mattsface

README.md

@@ -258,7 +258,7 @@ A Session created by the library sends a package-specific User-Agent:
 python-mlb-statsapi/<installed-version>
 ```
 
-For this release's currently declared package metadata that resolves to `python-mlb-statsapi/0.9.0`. The version is read from the installed distribution metadata, so it always matches the installed release. Only the `User-Agent` header is set; other Requests defaults such as `Accept-Encoding` remain intact, and the header carries no identifiers beyond the package name and version.
+For this release's currently declared package metadata that resolves to `python-mlb-statsapi/1.0.0`. The version is read from the installed distribution metadata, so it always matches the installed release. Only the `User-Agent` header is set; other Requests defaults such as `Accept-Encoding` remain intact, and the header carries no identifiers beyond the package name and version.
 
 Headers on a caller-injected Session are left untouched, so applications that set their own User-Agent keep it.
 

docs/http-transport.md

@@ -198,7 +198,7 @@ python-mlb-statsapi/<installed-version>
 With the package version currently declared in project metadata that resolves to:
 
 ```text
-python-mlb-statsapi/0.9.0
+python-mlb-statsapi/1.0.0
 ```
 
 The version comes from the installed package metadata, so it always matches