Fix edge cases in replace_emoji, demojize, and version functions

[sunnynguyen-ai]

This PR fixes several edge cases and improves error handling in core emoji functions:

• Add bounds checking for alias processing in demojize() - Prevents IndexError when alias list is empty or aliases are too short
• Use safe key access for emoji version data in version() - Handles missing 'E' key gracefully with default value
• Prevent IndexError and KeyError on malformed emoji data - Makes functions more robust against corrupted data

Fixes:

• emoji.replace_emoji("Hello 👋", replace="") now correctly returns "Hello "
• demojize() no longer crashes on empty/short aliases
• version() handles missing 'E' key gracefully

These changes improve the library's robustness when handling edge cases and malformed data.