[MIGraphX EP] Ensure we support all inputs for MatMulInteger and ConvInteger. (#21680)
… to int8 for now
Allow for models with biases/full input and only check for int8 support
in EP
### Description
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Allows for all inputs for MatMulInteger and ConvInteger to be supported
for prequantized models
### Motivation and Context
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- If it fixes an open issue, please link to the issue here. -->
Fixes issues when using prequantized models that contain weight biases
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Co-authored-by: Ted Themistokleous <tedthemistokleous@amd.com>