### Problem description
WerWolv/ImHex#1814
### Implementation description
1. Remove the flag that wrongly tells `ImFontAtlas` that it owns font
data, and remove that parameter from the function signature entirely
since now it is always `false`.
2. Rename `takeAtlas` to `getAtlas` since it no longer transfers
ownership as of b652565b57bd8a9aac2779b09f51f7bac26afca2.
fb249767f1