Fix duplicates ('Cav3.3' and 'Sleep spindle') in additionsToOntologies.csv

[pafonta]

BBP_nlx_0021 was associated to 'Thalamic reticular nucleus cell - non-GABAergic' and wrongly to 'Sleep spindle'. BBP_nlx_0022 was associated to 'Thalamic reticular nucleus cell - GABAergic' and wrongly to 'Cav3.3'.

'Sleep spindle' was associated to BBP_nlx_0021 (wrongly) and BBP_nlx_0025. 'Cav3.3' was associated to both BBP_nlx_0022 (wrongly) and BBP_nlx_0026.

Wrong mentions were corrected in the annotations by the following commits:

• https://github.com/BlueBrain/corpus-thalamus/commit/f2f2752e7406632a2998eaffac744b6d1a460f43
• https://github.com/BlueBrain/corpus-thalamus/commit/2d427b456f20e9bd9f94e8f5da2ecc441ebb29c8