Return 404 for invalid path: /release//File-Stat-Convert

[ranguard]

Return 404 for invalid paths, e.g. /release//File-Stat-Convert instead of a 500 - fix #3155

Please could you run perl tidy on this - I don't have the Perl setup

[codecov[bot]]

Codecov Report

All modified and coverable lines are covered by tests :white_check_mark:

Project coverage is 73.00%. Comparing base (9059e9d) to head (eafbb34).

Additional details and impacted files

```diff @@ Coverage Diff @@ ## master #3156 +/- ## ========================================== + Coverage 72.85% 73.00% +0.14% ========================================== Files 69 69 Lines 2391 2393 +2 Branches 338 339 +1 ========================================== + Hits 1742 1747 +5 + Misses 521 520 -1 + Partials 128 126 -2 ``` | [Files](https://app.codecov.io/gh/metacpan/metacpan-web/pull/3156?dropdown=coverage&src=pr&el=tree&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=metacpan) | Coverage Δ | | |---|---|---| | [lib/MetaCPAN/Web/Controller/Release.pm](https://app.codecov.io/gh/metacpan/metacpan-web/pull/3156?src=pr&el=tree&filepath=lib%2FMetaCPAN%2FWeb%2FController%2FRelease.pm&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=metacpan#diff-bGliL01ldGFDUEFOL1dlYi9Db250cm9sbGVyL1JlbGVhc2UucG0=) | `90.29% <100.00%> (+0.19%)` | :arrow_up: | ... and [2 files with indirect coverage changes](https://app.codecov.io/gh/metacpan/metacpan-web/pull/3156/indirect-changes?src=pr&el=tree-more&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=metacpan)

[ranguard]

3157 is better