Fixed integer underflow in OgreDistortionPass

[peci1]

🦟 Bug fix

Summary

I've noticed the code is prone to underflow because the distorted pixel values can be negative. Practically, the underflow was not a problem because the 4e9 values coming from the underflow never matched the condition to be lower than texture width. But it is an underflow and it deserves to be fixed.

Checklist

• Signed all commits for DCO
• Added tests
• Updated documentation (as needed)
• Updated migration guide (as needed)
• Consider updating Python bindings (if the library has them)
• codecheck passed (See contributing)
• All tests passed (See test coverage)
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