Dry the chicken thoroughly with paper towels, then season generously with salt and pepper. Heat the oil in a 12-inch skillet over medium-high heat until just smoking. Carefully lay 6 of the chicken thighs into the skillet, skin-side down; cook until golden, about 6 minutes. Flip the chicken over and continue to cook until the second side is golden, about 3 minutes. Transfer the chicken to a slow cooker. Using paper towels, remove and discard the browned chicken skin. Pour off all but 2 teaspoons of the fat left in the skillet and return to medium-high heat until just smoking. Brown the remaining chicken, transfer it to the slow cooker, and discard the skin.
. Pour off all but 2 teaspoons of the fat left in the skillet and return to medium heat until shimmering. Add the onions and ¼ teaspoon salt; cook, scraping the browned bits off the bottom of the skillet, until the onions are soft and translucent, about 4 minutes. Add the garlic, cinnamon, cardamom, and paprika; cook until fragrant, about 30 seconds. Add the apricots and 2½ cups of the chicken broth, scraping up any browned bits from the bottom. Turn the heat to high and bring to a boil. Transfer the mixture to the slow cooker.
Cover and cook on low until the chicken is almost tender, about 3 to 4 hours. Quickly stir in the chickpeas, replace the cover, and cook until the chicken is tender but not falling apart, about 1 hour longer.
Transfer the chicken to a carving board and tent loosely with foil to keep warm. Discard the cinnamon stick. Set the slow cooker to high. Whisk the flour with the remaining ½ cup chicken broth until smooth, then stir it into the slow cooker. Continue to cook on high until the sauce is thickened and no longer tastes of flour, 10 to 15 minutes longer. Stir in the cilantro and lemon juice. Season with salt and pepper to taste. Return the chicken to the slow cooker and allow to heat through before serving. Serve with lemon wedges.