--env splitIndex=0 not working in 1.25.0

We run our integration tests with the following command:

```
npx cypress run --component --browser chrome --headless --env split=4,splitIndex=0
```

Since 1.25.0, this will run all tests and no splitting will be performed. The following output is NOT shown any longer, so it appears cypress-split is completely silent in this case.

```
cypress-split: there are 444 found specs
the first 5 specs
- 1: foo.ts
- 2: foo2.ts
- 3: foo3.ts
- 4: foo4.ts
- 5: foo5.ts
cypress-split: chunk 1 of 4

```

However, any splitIndex like 1,2,3 will work fine.

I can workaround this issue by using --expose instead of --env.

Start by running the reported `npx cypress run --component --browser chrome --headless --env split=4,splitIndex=0` command with cypress-split 1.25.0, then compare it with splitIndex values 1, 2, and 3. Trace how the `--env` values are read and verify that splitIndex 0 produces the expected spec-count and chunk output and splits tests instead of running all specs.

Written by the indexing model from the issue text.