Fix duplicate --runtime-path in generated helix command (#40975)

While looking at some helix debug logs I noticed we pass the `--runtime-path` option twice:

```
Executed on dci-mac-build-083.local
+ ./RunTests.sh --runtime-path /tmp/helix/working/A68F0925/p --runtime-path /tmp/helix/working/A68F0925/p
```

Looks like this was an oversight from #35606, it's harmless but I thought I'd clean it up :)

src/libraries/sendtohelixhelp.proj

@@ -135,9 +135,9 @@
       We "exit /b" at the end of RunTests.cmd. Helix runs some other commands after ours within the batch script,
       so if we don't use "call", then we cause the parent script to exit, and anything after will not be executed.
     -->
-    <HelixCommand Condition="'$(TargetsWindows)' == 'true'">call RunTests.cmd --runtime-path %HELIX_CORRELATION_PAYLOAD%</HelixCommand>
+    <HelixCommand Condition="'$(TargetsWindows)' == 'true'">call RunTests.cmd</HelixCommand>
     <HelixCommand Condition="'$(TargetsWindows)' == 'true' and '$(HelixCorrelationPayload)' != ''">$(HelixCommand) --runtime-path %HELIX_CORRELATION_PAYLOAD%</HelixCommand>
-    <HelixCommand Condition="'$(TargetsWindows)' != 'true'">./RunTests.sh --runtime-path "$HELIX_CORRELATION_PAYLOAD"</HelixCommand>
+    <HelixCommand Condition="'$(TargetsWindows)' != 'true'">./RunTests.sh</HelixCommand>
     <HelixCommand Condition="'$(TargetsWindows)' != 'true' and '$(HelixCorrelationPayload)' != ''">$(HelixCommand) --runtime-path "$HELIX_CORRELATION_PAYLOAD"</HelixCommand>
   </PropertyGroup>