Fix bug where character goes into jump mode on slanting floors

[tkshnwesper]

Description

• Character displays run animation instead of jump animation on slanting tiles

Checklist

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• I open this PR to the develop branch.
• I have added a description of the change under [next] in CHANGELOG.md.
• I ran dart format --output=none --set-exit-if-changed . and has success.

Breaking Change

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• Yes, this is a breaking change (please indicate a breaking change in CHANGELOG.md).
• No, this is not a breaking change.

[RafaelBarbosatec]

Great! Thanks for contributing! LGTM!