Swift sneak 4 / 5 allowed players to sprint while sneaking in previous versions, like in 1.21.3 (Independent of MC-152728, you can start sprinting while sneaking in this case)
Probably due to the fix of MC-152728.
Not sure if this change is intentional, as this change wasn't documented.

How to reproduce:
1. Give yourself swift sneak 4 or 5 leggings in 1.21.3
/give @s netherite_leggings[enchantments=\{swift_sneak:5}]
2. Try to sprint while sneaking (Do not sprint before sneaking, this will cause MC-152728)

3. Repeat step 1~2 but in version 24w46a

You can also use a predicate to check if the player is sprinting, using this command below (in a repeating command block)
/execute as @p if predicate {"condition":"minecraft:entity_properties","entity":"this","predicate":{"type":"minecraft:player","flags":

}} run say SPRINTING

Observed Results:
The player doesn't start sprinting while holding down Ctrl and equipping a swift sneak 4 / 5 leggings.

Expected Results:
The player will start sprinting while holding down Ctrl and equipping a swift sneak 4 / 5 leggings, like in previous versions.