[curation] link figures and movies in assay READMEs

assays/RootLengthMeasurement/README.md

+
+# Root Length Measurement
+
+## Movie S1. Arabidopsis seedlings grown in a RoPod chamber have normal phenotype.
+
+The time-lapse movie of root growth illustrated and quantified in the Fig.1g-i. Seed germination and
+root elongation of seedling grown in the RoPod v24.3 are comparable to the growth under or on
+top of the growth medium in a Petri plate. Additionally, similar growth of wild-type WT) plants
+corroborates that RoPod provides favourable growth conditions for Arabidopsis plants. Images
+were acquired using SPIRO.
+
+
+![41598_2024_63226_MOESM1_ESM.mp4](assays/RootLengthMeasurement/dataset/41598_2024_63226_MOESM1_ESM.mp4)
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