Try CNN -> ViT assumption for IR insertion

[goodsong81]

• Update method setting logic to try CNN -> ViT assumption
• Update func test to use 'None' method to guess inside
• Update xfail test cases
  • Some models are actually CNNs
  • Some ViT-like models are working in CNN mode

[codecov[bot]]

Codecov Report

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

Project coverage is 91.97%. Comparing base (c497c01) to head (c3e73e1).

Additional details and impacted files

```diff @@ Coverage Diff @@ ## develop #48 +/- ## =========================================== + Coverage 91.93% 91.97% +0.03% =========================================== Files 19 19 Lines 1227 1233 +6 =========================================== + Hits 1128 1134 +6 Misses 99 99 ``` | [Flag](https://app.codecov.io/gh/openvinotoolkit/openvino_xai/pull/48/flags?src=pr&el=flags&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=openvinotoolkit) | Coverage Δ | | |---|---|---| | [dev-py310](https://app.codecov.io/gh/openvinotoolkit/openvino_xai/pull/48/flags?src=pr&el=flag&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=openvinotoolkit) | `91.97% <100.00%> (+0.03%)` | :arrow_up: | Flags with carried forward coverage won't be shown. [Click here](https://docs.codecov.io/docs/carryforward-flags?utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=openvinotoolkit#carryforward-flags-in-the-pull-request-comment) to find out more.

:umbrella: View full report in Codecov by Sentry.
:loudspeaker: Have feedback on the report? Share it here.